This paper reports on the development of an analytical method for the simultaneous determination of 4-methyl phenol, 4-hydroxybenzoic acid and five bile acids, namely cholic acid, glycochenodeoxycholic acid, chenodeoxycholic acid, deoxycholic acid, and hyodeoxycholic acid (logP 1.6–4.9) in urine, exploring porous acrylic polymers as unconventional solid-phase extraction sorbents before HPLC-MS/MS analysis. These materials, obtained by polymerization of high internal phase emulsions with different composition, were used in a miniaturized setting (µSPE), preliminarily in synthetic urine samples enriched with 200 ng mL−1 of each selected compound. It was found that the polyethylene glycol (PEG)-modified polymer combines good analytical performance, in terms of extraction efficiency (76–100

In the context of particle physics, different families of gaseous detectors are operated with fluorinated-gases which may break and form, among other species, free fluorine ions. Such species may react with water molecules present in the gas, leading to the formation of HF that could affect the long term performance of the detector (Capeans et al., 2010). To quantify these anions, ion selective electrodes (ISE) were employed in both large LHC gas systems as well as small R&D setups. All the tests described in this work were performed with gaseous detectors operating under strong irradiation. First, measurements were conducted on Resistive Plate Chambers (RPC) detectors installed at the CERN Gamma Irradiation Facility (GIF++) (J & auml;kel et al., 2014) [1] operated with different gas mixtures and under gamma irradiation of different intensities. The F-production was studied for the RPC standard gas mixture (90-95.2% C2H2F4 + 4.5%-10% iC4H10 + 0.3% SF6) and compared to different CO2 and R1234ze gas mixtures. Moreover, different concentrations of SF6 were investigated to understand if and how SF6 could affect fluorides production. The F-production was studied for the ALICE Muon IDentifier by means of ISE and gas chromatography and the results from LHC RUN2 and RUN3 measurements are presented (Mandelli et al., 2019) [2]. Finally, first results on F-production in Ar/CO2/CF4 gas mixtures were obtained for different CF4 fractions with a dedicated laboratory setup. Initial tests and considerations regarding the setup are documented.

Graphitic carbon nitride (g-C3N4) is a promising metal-free photocatalyst whose activity is often enhanced by nitrogen vacancies, though their microscopic role remains unclear. Using advanced ab initio calculations with large periodic supercells, we show that long-range buckling is essential to correctly evaluate defect energetics and thus determine the stability of distinct vacancy configurations. The most stable defects are found to introduce localized in-gap states corresponding to shallow acceptor and deep donor levels. These features explain (i) the experimental red-shifted absorption and (ii) suppressed photoluminescence observed in N-deficient g-C3N4 samples. Most importantly (iii) energy-level alignment at the water-semiconductor interface explains the enhanced photocatalytic reduction and reduced oxidation activity reported experimentally. Overall, our results provide a unified microscopic picture that quantitatively connects defect-induced electronic structure changes and experimental observables, offering a concrete predictive strategy for designing defect engineered carbon nitride and related metal-free photocatalysts.

This work presents a novel application of biochar as a new-generation sorbent to bioanalytical sample preparation. The carbonaceous material produced by pyrolysis of vegetal wastes (orange and pumpkin peels) at 650°C was easily attached (∼ 4 mg) to a small magnetic stir bar (8 × 3 mm), enabling a novel stir bar sorptive microextraction protocol to be performed directly in the HPLC-MS vial. The device was first tested in synthetic saliva samples (1 mL) observing sorption equilibrium in 1 h contact time and full elution was achieved using 300 µL 1 % v/v acetic acid ethanol solution after 30 min. Under the selected conditions, recovery in real saliva, spiked with each analyte in the range 0.5-5 ng mL-1, was in the range 88%-112%, with good inter-day inter-batch device-to-device precision (RSD < 18%, n=3), and no need for additional clean-up. Reusability tests confirmed that the device retains its sorption/desorption efficiency over at least 20 consecutive cycles. Additionally, the greenness of this biochar-based “in-vial” approach as a new stir bar sorptive microextraction was proven by using different dedicated software. The practical applicability of the procedure was demonstrated in real saliva samples from healthy volunteers.

The in-vial microextraction technique is emerging as an alternative sample treatment, as it integrates sorbent preparation, adsorption, and desorption of analytes in a single device before instrumental analysis. In this work, the applicability of polycaprolactone polymeric film, recently used for the in-vial microextraction of sex hormones from environmental waters, is studied in a low-capacity format for unconjugated sex hormones determination in biological samples by HPLC-MS/MS. Its performance was evaluated in urine and serum, achieving extraction in a short time (10 and 30 min, in turn) and satisfactory elution with ethanol, with recovery in the range of 65–111% in urine, 55–122% in bovine serum albumin (BSA) solution, and 66–121% in fetal bovine serum (FBS). In the case of protein matrices, a dilution to 20 g L−1 protein content and washing step (3 × 1 mL ultrapure water) afore the elution are required to achieve clean extract, as verified by a Bradford assay. Matrix-matched calibration was used for quantification, obtaining correlation coefficients greater than 0.9929; limits of detection and quantification were in the range of 0.01–0.65 and 0.03–1.96 ng mL−1 in urine, 0.02–0.8 and 0.05–2.5 ng mL−1 in BSA, and 0.02–1.0 and 0.06–3.0 g mL−1 in FBS, respectively. The in-vial polycaprolactone film proved to be reusable for several cycles (up to ten), and the greenness assessment revealed a good adhesion to green sample preparation principles. All these achievements further strengthen its feasibility for efficient extraction/clean-up of trace sex hormones in complex biological samples.

Photocatalytic nitrogen fixation (PNF) offers a green route to ammonia synthesis under ambient conditions. We present a scalable synthesis of BiOBr/g-C3N4 heterojunctions and identify that the composition with 10 wt% BiOBr achieves similar to 20 & micro;mol g-1 h-1 ammonia production-outperforming pristine materials of the heterojunction. Mechanistic investigations reveal that enhanced activity stems from efficient charge separation, supported by time-resolved spectroscopy showing extended carrier lifetimes. DFT calculations reveal that the catalytically active (010) surface of BiOBr exhibits favorable band alignment with g-C3N4 and enables downhill electron transfer to the N2/NH3 redox level. Crucially, this surface hosts localized electron polarons, which act as reactive sites for nitrogen reduction. In contrast, the (001) surface lacks such features, explaining the reduced performance at higher BiOBr loadings. These findings establish a direct link among surface structure, charge dynamics, and catalytic functions, offering design principles for next-generation photocatalysts for sustainable ammonia production.

Due to the growing commercial availability of cannabinoids as active principles for recreational use, the use of preparations including among the others extracts and edible products (e.g., gummy sweets) is gaining popularity when compared to smoking, the more classical method of cannabinoid consumption. In this context, along with the widely known cannabidiol (CBD) and D9-tetrahydrocannabinol (D9-THC), hexahydrocannabinol (HHC) and D8-tetrahydrocannabinol (D8-THC) have recently been openly sold in a range of products worldwide, having been neglected by some regulatory authorities. When dealing with complex matrices such as edibles, the commonly available methods for the identification and quantification of natural and semi-synthetic cannabinoids-GC-MS and LC-MS-must be implemented. In this work, we describe a GC-MS protocol for the analysis of the different cannabinoids present in seized gummy sweets after liquid extraction of the active ingredients. The protocol has been optimized and validated (according to the current guidelines) by using spiked cannabinoid-free commercially available gummies. The procedure has been exploited for the identification and quantification of the cannabinoids (both natural and semisynthetic) present in six different types of seized recreational gummies and allowed us to hypothesize the origin of the cannabinoid-natural or synthetic-and in this last case also the synthetic strategies used to obtain them. Note-worthily, besides the cannabinoids already described in literature, our approach also pointed out the presence of a hexahydrocannabinol analogue (hexahydrocannabinonol, HHC-C9) as well as cis-9,10-octadecanoamide (oleamide), a modulator of CB1 cannabinoid receptor that exhibits a cannabinoid-like action.

Sound suppressors critically modify barrel overall length and ballistic performances of hosting guns and are therefore expected to influence the patterns of the plumes of gunshot residues (GSR) reaching the targets. Despite the forensic interest, in recent years, a single paper was published on the variations induced by the use of a suppressor in the spatial distribution of visible soot clouds on close targets and in the number of a few selected classes of GSR particles detected by scanning electron microscopy. A different approach, based on x‐ray fluorescence (XRF) and inductively coupled plasma‐optical emission (ICP‐OES) spectroscopies, that points to most of the metallic elements ejected from the barrel, is suggested here. The confirmed effect of a sound suppressor up to a distance of 20 cm is to gather the cone of particles reaching the target. Despite this pattern modification, the global concentrations of the ammunition‐related elements of interest (Pb, Ba, Sb, Cu) on targets cannot be considered significant (i.e., with 95% confidence) reduced by the use of a suppressor, due to the high intra‐specimen and inter‐specimen ICP‐OES data dispersions. Differently, the hypothesis of a role of homemade suppressors in enriching GSR populations in Fe is supported by our results. The presence of iron is indeed the only indication of the actual use of a suppressor, a piece of information that is useful for the correct interpretation of the lead patterns visualized on targets for muzzle‐to‐target determination.

It is well-known that ceria nanoparticles (CNPs) exhibit significant antioxidant activity, offering potential applications in the treatment of ROS-related pathologies. This activity of CNPs as a nanozyme is typically interpreted by considering Ce(III)/Ce(IV) equilibria on the nanoparticles' surface. However, the validity of this mechanism has never been directly proven in a biological context. Furthermore, it is often overlooked that after endocytosis, CNPs are compartmentalized within endolysosomes, while ROS are primarily located in the cytoplasm, making their direct interaction difficult. This study presents chemical and biological evidence supporting an alternative mechanism of action. By utilizing synchrotron μXRF and μXANES analysis on individual cells, the study shows that the amount of Ce(III), the species responsible for the antioxidant activity, increases linearly with time within the endolysosomes, where CNPs are accumulated, and in their vicinity. Such an increase can be explained by the release of Ce3+ ions resulting from a partial reductive dissolution of CNPs in the acidic environment of the endolysosomes. The Ce3+ ions can then cross the endolysosomal membrane, reaching the cytosol, where they can exert their reducing activity on ROS. In fact, neutralizing the acidic endolysosomal pH results in a complete inhibition of the CNP activity. Consequently, CNP antioxidant activity should be regarded as the result of redox processes that extend beyond the nanoparticles surface but involve complex dissolution equilibria.

The original evaluation of a porous polymeric biomaterial as sorbent phase for analytical sample preparation is presented. The apolar nature of the base butyl acrylate-based polymer was tailored by embedding hydrophilic moieties of either 4-hydroxybutylacrylate or polyethyleneglycole mono methacrylate. This allowed, through the one-pot approach, to prepare hydrophilic-lipophilic balanced materials, which were then tested for the multiclass extraction of steroids from water and milk samples. As demonstrated through packed-cartridge solid-phase extraction (SPE), increasing the sorbent hydrophilicity improved the sorption affinity for the less lipophilic steroids, i.e. glucocorticoids, achieving quantitative uptake for all the probe contaminants on the PEG-modified polymer. The latter was applied to recovery tests at the ng/L level in tap and drinking water samples (25 mL), observing a complete elution in a single fraction of ethanol, thus achieving recovery in the range 60-125 % for most analytes (inter-day RSD < 19 %, n = 3). Reusability tests in tap water demonstrated the durability of the polymer for five consecutive sorption/elution cycles, with unchanged performance. The same material was functional to the extraction/clean-up of the steroids in milk samples (1 mL), at the micrograms per litre level, without sample deproteinization, as proved by SPE in whole, partially skimmed and lactose-free dairy milk samples, and bottled infant formula milk. After sample loading and washing with 5 % v/v acetonitrile acidic aqueous solution, the analytes were single-step eluted in pure ethanol, obtaining recovery ranging from 50 to 110 % (inter-day RSD < 12 %, n = 3), and clear extracts to be analyzed by HPLC-MS/MS. The greenness assessment proved the sustainability of this SPE procedure.

BACKGROUND:The sustainability of sample treatments is a hot topic that can be addressed focusing on miniaturization of techniques and design of more efficient and sustainable sorbents. In such scenario, in-vial microextraction is increasingly reported as a reliable alternative to other solid-phase extraction setups, as integrates sampling, adsorption and desorption in a single device before instrumental analysis. Polymeric thin films have proven to be a versatile and efficient material for microextraction processes, but more attention has to be paid to the preparation steps both in terms of nature of polymer and possible co-extractant, and of solvents applied during the solubilization process. RESULTS:An in vial-microextraction device for sex hormones was fabricated using as the extractant a thin film made of a biodegradable polymer (polycaprolactone, PCL) directly formed on the bottom wall of a glass vial. The greenness assessment of the film preparation results in the selection of an environmentally friendly solvent (methyl-tetrahydrofuran) for PCL solubilization. After evaluation of key parameters (contact time, desorption solvent and conditions), efficient adsorption-desorption cycle is completed in 30 min. High simplicity, low sample manipulation (two steps), quantitative adsorption and recovery (EE% > 70; R% > 60 for most analytes, respectively) determined by HPLC- MS/MS greatly improve sample throughput and the greenness of the method (0.66 by AGREEprep and 7.58 by SPMS). The method was successfully validated in actual water samples, showing low limits of detection (2-35 ng L-1), satisfactory linearity (0.5-50 μg L-1), and limited matrix effects (<10 % for river and <25 % for wastewater). SIGNIFICANCE:This polycaprolactone film proved to be a biodegradable and sustainable sorbent towards sex hormones. Its applicability in the in-vial thin film microextraction ensures the whole sample treatment in the same vial with high throughput, low energy and solvent consumption, keeping unchanged performance for multiple cycles. The method combines a green sample treatment with accurate detection and high sensitivity by HPLC-MS/MS, representing significant progress in miniaturized devices for environmental scope.

The development of sustainable materials toward efficient pollutant removal is crucial for water remediation. Following a waste-to-wealth approach, we report a novel preparation of biodegradable film embedded with a biomass-derived activated char and its effective application for the removal of fluoroquinolones from aqueous solutions. The presence of these antimicrobials contributes to the worrying increase of environmental antimicrobial resistance and ecotoxicity since they are emerging and harmful pollutants, and requires effective solution for their removal. The impact of different parameters on the sorptive performance was evaluated (e.g., type of polymeric support and char, amount of char), revealing that the removal process strongly depends on the type and amount of activated char used, whereas the polycaprolactone only acts as a support immobilizing the char and facilitating the sample treatment. By simply suspending the film in the aqueous sample, it is possible to adsorb the target contaminants, with removal efficiency up to 80 % in 240 min and satisfactory cumulative sorption capacity (Q up to 14,000 μg g-1) in competitive conditions. The sorption process obeys second-order kinetics in all the water samples tested (potable water, river water and wastewater). Notably, the film demonstrated continued stable removal capabilities over multiple uses (up to five). This work provides a new strategy for exploring a novel and efficient film for water purification.

In the field of green sample preparation, new challenges are emerging for guaranteeing sustainability of analytical procedures and remarkable efforts have been made to develop materials from natural and/or renewable sources. In such a scenario, biochar is emerging as alternative sorbent with low economic and environmental impact. It is a carbon-rich material derived from the thermochemical conversion of biomass and waste and endowed with excellent textural properties such as high specific surface area and meso- and microporosity, and functional groups that are fundamental for the sorption behaviour, a key point in the analytical performance of biochar. These outstanding properties generated a growing interest in the use of biochar-based sorbents in sample preparation. In this context, this review provides an overview of the last 4-year applications of biochar in extraction techniques through an evaluation of greenness of the sample preparation procedures. At this purpose, two metric tools specific for the sample preparation, as AGREEprep and Sample Preparation Metric of Sustainability (SPMS), have been selected to give comprehensive evaluations about greenness, considering multiple criteria but with different weights and intervals in the parameters. Indeed, the papers here reviewed received in SPMS scores ranging from 5.16 to 10, and in AGREEprep from 0.16 to 0.7, evidencing there is space for improving extraction procedures involving biochar-based sorbents.

A biochar-based vial wall sorptive extraction (VWSE) was developed for multiclass steroid determination in waters. Coupling biochar with this user-friendly but still undervalued extraction technique provided a green sample preparation functional to HPLC-MS/MS quantification. Among the biochar samples prepared from different vegetal wastes, the most promising in terms of sorption affinity was obtained by pyrolysis of pumpkin peels under optimized conditions (650 °C, 4 h), which yielded a sorbent endowed with polar groups. After immobilization on the inner wall of small sampling tubes, the uptake of steroids was first investigated in potable water. The coated vial provided good extraction efficiency (90 min orbital shaking) not only for sex steroids but also for glucocorticoids (logP 1.9–2.5) possibly due to interaction with biochar oxygenated groups. The uptake of the 17 targets joined to pre-concentration allowed determination of these contaminants at environment-relevant concentrations, using only 10 mL samples. The possibility of sampling and extraction on-site in the same container coupled with the good sorption behaviour followed by quick (10 min) and exhaustive elution in 2.5 mL ethanol, a safe and green solvent, make the procedure green, with a streamlined workflow showing good throughput (15 samples treated simultaneously). Recoveries in the range ∼65 %-120 % (40 %-108 % for glucocorticoids) were obtained in tap, lake, river, lagoon water and wastewater treatment plant effluent samples, with inter-day inter-batch device-to-device RSD < 19 % (n = 3). The coated-vial was reusable for at least 20 samples contributing to the positive greenness scores obtained through specific metrics.

Designing innovative photocatalysts for nitrogen photofixation is becoming crucial for the development of carbon-neutral ammonia production. Metal halide perovskites (MHPs) provide a rich library of materials with an easy tuning of the semiconductor bandgap in order to integrate them in devices with different functionalities. An under-explored path is their exploitation to run a wide range of photoredox reactions mediated by solar light. Herein, heterojunction is developed based on the vacancy-ordered double-perovskite Cs2SnBr6 and carbon nitride nanosheets and demonstrate its ability in running the nitrogen photofixation reaction to produce ammonia under solar light. An investigation is done on full Cs2SnBr6/g-C3N4 system and an optimal range providing an outstanding ammonia evolution rate up to 270 mu mol g-1 h-1is identified, which is quantified by means of ion selective electrode. Mechanistic insight into the photofixation reaction is obtained through a combination of advanced spectroscopy and computational modeling. Efficient ammonia production stems from an effective charge transfer from the perovskite to the nitrogen vacancies on the carbon nitride enabled by the proposed absence of self-trapped excitons in Cs2SnBr6, which also provides additional reactive sites through bromide vacancies. This work paves the way to MHP-based catalyst design strategy for sustainable ammonia production.

This study investigates the groundwater quality of an aquifer located in medium-populated area of the Ticino Valley with strong agricultural vocation. Two monitoring campaigns were carried out according to the phases of rice cultivation (pre- and post-flooding) on the subsurface and surface irrigation network, Ticino River and wastewater effluents, highlighting a diffuse contamination. The isotopic analyses evidenced mixing phenomena, with both contributions from local rainfall and irrigation network. Combining chemical and microbiological approaches, the anthropogenic impact was evaluated by analysing a selection of traditional and emerging pollutants, such as pesticides, antibiotics and hormones, and assessing the extent of enterobacterial contamination and potential antibiotic resistance genes. Most of the investigated contaminants were found in concentrations from 0.1 ng/L to 632 ng/L, with the exception of Glyphosate and AMPA up to 5 and 20 mg/L, respectively. Even at these low concentrations, contamination of water resources is a serious issue because long-term exposure to such pollutants may cause detrimental effects. The most frequently detected pesticide was the fungicide Tricyclazole, while glucocorticoid Dexamethasone was the most frequent steroid hormone. Noteworthy is the ubiquity of Trimethoprim and a recurrent presence of fluoroquinolones. The occurrence of antibiotics at most sites, although at very low levels, is of environmental and public health concern, as they exert a selective pressure on bacterial populations, allowing the development of antibiotic resistant microbes, as highlighted by microbiological investigations. Indeed, a high microbial load was found in both campaigns, in particular in those sampling sites close to wastewater treatment plants, with the b-lactams and quinolones classes of antibiotics as the most affected by the phenomenon of resistance. (c) 2025 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

This paper shows the results collected in lab-scale experiments for photocatalytic H2 evolution from rice industry wastewater, by using a cheap and eco-friendly graphitic carbon nitride catalyst, one-pot prepared by the sacrificial template method. The final effluent from the production of "rice milk" beverage proved to be really rewarding compared to pure water, highlighting the possibility of taking advantage of a sugar-rich matrix to boost H2 formation. After preliminary experiments in glucose aqueous solution, yielding a maximum gas evolution above 1000 mu moles g-1 h-1, the study moved on to wastewater and the operational conditions were optimized through designed experiments, under simulated solar light. Production of about 150 mu moles g-1 h-1, at least 380-fold greater than production from neat water, was achieved by working with just 0.5 g L-1 of catalyst directly in the raw effluent, thus limiting the amount of metal co-catalyst and avoiding sample dilution. The reproducibility of the process was good, with relative standard deviations below 12% (n = 3). The production was also verified under natural sunlight, obtaining a mean production of nearby 115 mu moles g-1 h-1. The sustainability of this photocatalytic setup is strengthened by the recyclability of the catalyst, which maintains its photoactivity for at least four treatments.

Feathers are commonly used to monitor trace elements in birds, including heavy metals. Typically, a single feather is analyzed to avoid harming living birds, assuming it reflects the organism’s overall contamination. To verify this assumption, we analyzed mercury concentrations in 12 flight and contour feathers from 25 barn swallows Hirundo rustica (16 adults and nine juveniles) that had died accidentally in a colony of the Po Plain (northern Italy). The median concentration in all feathers examined was 1.03 µg g−1 in adults (range 0.76 µg g−1–1.30 µg g−1) and 0.39 µg g−1 in juveniles (range 0.28 µg g−1–0.71 µg g−1), which is consistent with the results of similar research carried out on other world regions. No significant differences were observed between sexes, whereas marked differences were observed between adults and juveniles. In adults, mercury concentration was similar across remiges, rectrices, and contour feathers while in juveniles it was higher in contour feathers than in flight feathers. Mercury accumulation was highest in primary remiges and contour feathers, accounting for 67.6% of total mercury in adults and 77.5% in juveniles. However, primary remiges cannot be collected from live adults due to their importance in flight. In juveniles, contour feathers carry about 50% of total mercury, suggesting ventral and dorsal plumage may be useful for assessing mercury burden. Our findings are consistent with the hypothesis that mercury accumulation in feathers aids detoxification, with early-molted feathers (primary remiges and contour feathers) containing higher mercury levels than those replaced later (rectrices and secondary remiges).

The use of sewage sludge as a soil improver has been promoted in agroecosystems. However, sludges can contain toxic trace elements because of suboptimal wastewater treatment. Nonetheless, field studies investigating the negative effects of these practices on pollinators are lacking. We collected honeybees from an area where sewage sludge use is widespread, and one where it is precluded. Trace elements in soils and bees were quantified. Cadmium, chromium, lead, mercury, and nickel were investigated because they were the least correlated elements to each other and are known to be toxic. Their levels were related to oxidative stress and energy biomarkers, midgut epithelial health, body size and wing asymmetry of honeybees. We found increased carbohydrate content in sites with higher cadmium levels, increased histological damage to the midgut epithelium in the sewage sludge area, and the presence of dark spherites in the epithelium of bees collected from the sites with the highest lead levels. Finally, we found that honeybees with the highest lead content were smaller, and that wing fluctuating asymmetry increased in sites with increasing levels of mercury. To the best of our knowledge, this is the first comprehensive study of the concentration and effects on honeybees of trace elements potentially deriving from soil amendment practices.

Designing innovative photocatalysts for nitrogen photofixation is becoming crucial for the development of carbon neutral ammonia production. Metal halide perovskites (MHPs) have been demonstrated to be effective materials to run a wide range of photoredox reactions mediated by solar light. Herein, we develop an innovative heterojunction based on the vacancy-ordered double perovskite Cs2SnBr6 and carbon nitride nanosheets and demonstrate its ability in running the nitrogen photofixation reaction to produce ammonia. We explore the full compositional range for the Cs2SnBr6/g-C3N4 system and identify an optimal range providing an ammonia evolution rate up to 260 μmol g-1 h-1, the highest value reported to date for a MHP-containing catalyst. Mechanistic insight into the photofixation reaction promoted by the heterojunction was obtained through a combination of advanced spectroscopy and computational modelling. Efficient ammonia production stems from an effective charge transfer from the perovskite to the nitrogen vacancies on the carbon nitride enabled by the absence of self-trapped excitons in Cs2SnBr6 which also provides additional reactive sites through bromide vacancies. This work, reporting an efficient MHP-based heterojunction for nitrogen photofixation and a clear definition of the underlying reaction mechanism, provides a catalyst design strategy that may pave the way for sustainable ammonia production.