Thermal oxidation of bulky carbon nitride (C3N4, CN) to expose more active sites is an important method to improve the activity of the as-prepared CN nanosheets. Unfortunately, the yield of thermal oxidation is low. Herein, we report dual-deficient CN (DDCN) ultrathin nanosheets engineered with nitrogen vacancies and cyano groups by two-step bottom-up thermal polymerization of belt-like melamine with a high yield of 65 %. Featured with abundant exposed active sites, short charge migration distance, wide visible-light absorption, quick charge separation/transfer, enhanced oxygen adsorption ability and 2e oxygen reduction reaction selectivity, the DDCN exhibits a high H2O2 production rate of similar to 1031 mu mol g(1) h(1), which is 19.5 times that of CN (53 mu mol g(1) h(1)) under visible light irradiation (lambda >= 420 nm). Specifically, the apparent quantum yield (AQY) of DDCN reached 10.7 % at 420 nm. This study provides a facile dual-defect engineering method to develop highly efficient ultrathin CN-based photocatalysts.

Photoreduction of CO2 and H2O into fuels and value-added chemicals is an effective solution to address global energy issues. However, developing photocatalysts with high activity and selectivity remains a major challenge. Herein, we report Ag nanoparticles (NPs) loaded FeVO4 (FVO) composite photocatalyst for highly efficient and selective photoreduction of CO2 to CO. Under a 300 W Xe lamp irradiation, the optimal Ag-1-FVO catalyst exhibits a CO yield of 255.4 mu mol g(-1) h(-1) and a CO selectivity of 99.7 %, which are dramatically higher than those of pure FVO alone. The significantly enhanced photocatalytic performance could be attributed to Ag NPs on the surface of FVO, which improve the separation efficiency of photogenerated carriers and promote the adsorption/activation of CO2 molecules. This study suggests that modification of semiconductor photocatalysts with Ag NPs is an effective method for enhancing the CO2 photoreduction activity.

The increased light absorption, reactive sites, CO 2 adsorption/activation, and desorption energy barrier of CO* in Co/TiO 2 –TiN synergistically account for the selective photothermocatalytic CO 2 reduction into CH 4 .

Interfacial electron transfer between an inorganic semiconductor and a metal-organic framework (MOF) is the key to photocatalysis in a composite photocatalytic system. The construction of structural defects in a single semiconductor or MOF has been regarded as an effective method for enhancing its photocatalytic performance. However, how the microenvironment modulation of photocatalytic sites between defective semiconductors and defective MOFs (quasi-MOFs) affects photocatalytic disinfection activity is worth studying. Herein, the integration of MOFs and semiconductors and their crystal defect construction is achieved by directly dropping ZIF-8 suspension onto the bismuth vanadate (BiVO4) nanoarray and subsequently activating it through low-temperature (300 °C) calcination under an N2 atmosphere. Compared with the original BiVO4 nanoarray, defective BiVO4 nanoarray (BiVO4-N2), and BiVO4-ZIF-8 nanoarray, (BiVO4-ZIF-8)-N2 exhibits enhanced photocatalytic disinfection activity (6.63 log10 CFU mL-1 after 4 h of simulated sunlight irradiation) due to its improved sluggish kinetics of electron transfer. In situ irradiated operando near-ambient pressure XPS (NAP-XPS) confirms its interfacial electron transfer, which can greatly modulate the microenvironment of the photocatalytic site and thus lead to efficient photocatalysis. This work presents a simple strategy to adjust the microenvironment of the photocatalytic sites between ZIF-8 and semiconductors to optimize photocatalytic bactericidal performance.

Visible-light-driven photocatalytic hydrogen production is one of the ideal green technologies for solar-to-chemical energy conversion. Carbon nitride (C3N4, CN) has been attracting extensive attention for its suitable band structure and stability, but the efficiency of photocatalytic hydrogen evolution is low due to insufficient visible-light absorption and rapid charge recombination. Herein, we develop a novel (F, K)-co-doped CN (FKCN) catalyst via a facile thermal polymerization approach using KOH-modified melamine and NH4F as the dopant precursors. The FKCN catalyst demonstrates broadened light absorption, significantly enhanced charge separation, and excellent cyclic stability. And the optimal F(0.15)K(6)CN catalyst achieves a hydrogen evolution rate of as high as 3101.5 μmol g−1 h−1 (12-fold that of pristine CN) under visible-light irradiation (λ ≥ 420 nm), which is among the best element-doped CN photocatalysts. This work highlights the effectiveness of a multi-element doping strategy in designing CN-based photocatalysts for efficient hydrogen evolution.

Powering the electrochemical nitrate reduction reaction (NO 3 ⁻RR) by renewable energy is a sustainable way to restore the environment and produce nitrogen–hydrogen compounds. However, the process requires multiple electron transfers and complex reaction paths, making it essential to understand the reaction mechanisms at the molecular level. In this regard, 2D materials attract significant interest due to their large surface area, tunable electronic structures, and suitability as model catalysts for studying structure–activity relationships. Advances in the use of 2D materials in the electrocatalytic NO 3 ⁻RR and C–N coupling reactions are analyzed and elucidated the influence of various 2D catalyst design strategies on reaction mechanisms. Using advanced in situ/operando measurement techniques, conducting rigorous theoretical analyses, and scaling up industrial electrolyzers are pivotal to unlocking the practical potential of the NO 3 ⁻RR and beyond. A map for developing next‐generation electrocatalysts and devices is provided to enable a sustainable and efficient nitrogen cycle using electrocatalysis.

Constructing a heterojunction is considered one of the most effective strategies for enhancing photocatalytic activity. Herein, we employ Ta3N5 and tubular graphitic carbon nitride (TCN) to construct a Ta3N5/TCN van der Waals heterojunction via electrostatic self-assembly for enhanced photocatalytic H2 production. SEM and TEM results show that Ta3N5 particles (~300 nm in size) are successfully anchored onto the surface of TCN. The light absorption capability of the Ta3N5/TCN heterojunction is between those of Ta3N5 and TCN. The strong interaction between Ta3N5 and TCN with different energy structures (Fermi levels) by van der Waals force renders the formation of an interfacial electric field to drive the separation and transfer of photogenerated charge carriers in the Ta3N5/TCN heterojunction, as evidenced by the photoluminescence (PL) and photoelectrochemical (PEC) characterization results. Consequently, the optimal Ta3N5/TCN heterojunction exhibits a remarkable H2 production rate of 12.73 mmol g−1 h−1 under visible light irradiation, which is 3.3 and 16.8 times those of TCN and Ta3N5, respectively. Meanwhile, the cyclic experiment demonstrates excellent stability of the Ta3N5/TCN heterojunction upon photocatalytic reaction. Notably, the photocatalytic performance of 15-TaN/TCN outperforms the most previously reported CN-based and Ta3N5-based heterojunctions for H2 production. This work provides a new avenue for the rational design of CN-based van der Waals heterojunction photocatalysts with enhanced photocatalytic activity.

The efficiency of CO2 photoreduction is often limited by the low reactivity of CO2 molecules and the rapid recombination of photogenerated charge carriers in most of the photocatalysts developed so far. In this study, we report a newly developed p-type Bi2Te3/SrTiO3 (pBT/STO) nanocomposite for efficient CO2 photoreduction. Upon light irradiation, the thermoelectric pBT with a strong light absorption capacity generates the photothermal effect favoring the activation of CO2 molecules. Meanwhile, a temperature gradient formed in pBT induces a thermoelectric field via the Seebeck effect, which promotes the charge carriers’ separation/transfer. In addition, the excellent electric conductivity and large work function render pBT an efficient cocatalyst for further improving the charge carriers’ separation/transfer. Owing to the synergistic photothermoelectric (PTE) effect on activation of CO2 molecules and promotion of charge separation/transfer, the efficiency of CO2 photoreduction over pBT/STO is significantly enhanced. We achieve the highest CO evolution rate of 28.0 μmol·gcat−1·h−1 over the optimal pBT(3)/STO, which is 12.8 times that of pure STO. This work suggests that a thermoelectric material and a semiconductor can be incorporated into a nanocomposite system for efficient CO2 reduction via the synergistic photothermoelectric effect on activating the CO2 molecules and promoting the charge carriers’ separation/transfer.

The development of effective water purification systems is crucial for controlling and remediating environmental pollution, especially in terms of sterilization. Herein, we demonstrate elaborately designed composite nanosheets with a sandwich structure, composed of two-dimensional (2D) Ti3C2 MXene nanosheet core and conformal ZIF-8 ultrathin outer layers, and their potential applications in photocatalytic sterilization. The study results indicate that the conformal ZIF-8-MXene nanosheet exhibits an expanded light absorption range (826 nm), improved photothermal conversion efficiency (6.2°C s−1), and photocurrent response, thus boosting photocatalytic sterilization efficiency (6.63 log10 CFU mL−1) against Escherichia coli under simulated sunlight within 90 min. Interestingly, 2D ZIF-8 layers exhibit positive zeta potential (19 mV), good hydrophilicity (40.6°), and local photogenerated-hole accumulation, possessing efficient bacteria-trapping efficiency. Membrane filters fabricated from optimized composite nanosheets exhibit an outstanding bacteria-trapping and sterilization efficiency (almost 100%) against Escherichia coli under simulated sunlight within 30 min of the flow photocatalytic experiments. This work not only presents a rational structural design of the conformal and ultrathin anchoring of ZIF-8 onto a 2D conductive material for bacteria-trapping and sterilization, but also opens new opportunities for using metal–organic frameworks in photocatalytic disinfection of drinking water.

Photoreduction of CO2 and H2O into fuels and value-added chemicals is a promising green technology for solar-to-chemical conversion. However, improving the conversion efficiency with regulated product selectivity is a big challenge due to the sluggish dynamic transfer and insufficient active sites. Herein, we report on Pt single atoms anchored porous C3N4 nanosheet photocatalyst (Pt1@CN) with Pt–N4 coordination for stable and efficient CO2 photoreduction using H2O as reductant. The Pt1@CN exhibits an evolution rate of 84.8 μmol g−1 h−1 with nearly 100% CO selectivity, outperforming most previous C3N4-based single-atom photocatalysts. Experimental and DFT calculation results reveal that the Pt–N4 coordinated active sites promote the photogenerated electron transfer, CO2 adsorption/activation, *COOH generation, and *CO desorption, thus accounting for the significantly improved CO2 photoreduction activity with ∼100% CO selectivity. This study provides a deep insight into the significant roles of single-atom active sites in enhancing the CO2 photoreduction activity and regulating the product selectivity.

A series of low-dose high-valence Ti4+ doped MIL-53-NH2(Fe) photocatalysts were synthesized for visible-light-driven CO2 reduction. The highest CO2-to-CO conversion rate of Ti4+ doped MIL-53-NH2(Fe) was 7.24 mmol g(-1) h(-1) and the highest CO selectivity was 94% in acetonitrile solvent using [Ru(bpy)(3)](2+ )and triethanolamine.

As a promising technology to mitigate global carbon emissions, photothermal catalytic CO 2 reduction remains a great challenge in increasing the conversion efficiency and regulating the product selectivity. Herein, a series of phase‐separated Ni–Mo alloy catalysts for efficient photothermal CO 2 reduction with tunable CO selectivity is reported. With the increase of Mo content, the evolution rate and selectivity of CO increases. The optimal catalyst Ni 1 Mo 1 achieves 32.1% CO 2 conversion with 98.0% of CO selectivity and 71.1 mmol g cat −1 h −1 of CO evolution rate under a 300 W xenon lamp irradiation. Further increasing the Mo content reduces the CO evolution rate while maintaining the high CO selectivity. In the mechanistic study, it is revealed that the Ni–Mo alloy with an appropriate Ni/Mo ratio (e.g., Ni 1 Mo 1 ) possesses a modified electronic structure with more negative d‐band center, which increases the light absorption, reduces the H 2 dissociation, and favors the CO desorption, thereby leading to efficient and selective photothermal reduction of CO 2 to CO. In this work, a viable strategy to design nickel‐based catalysts is provided for efficient and selective photothermal CO 2 reduction via composition‐mediated modification of electronic structure.

Efficient metal-organic frameworks (MOFs) photocatalytic bactericidal catalysts are urgently needed in water purification. Herein, a Fe-MOF (MIL-88B-NH2(V1Fe5) with promoted electron transport was achieved by vanadium (V) ions doping and V/Fe ratio optimization, showing excellent photocatalytic bactericidal activity against E. coli under visible light irradiation (99.92%). The efficient antibacterial mechanism, V as a Ti-like mediator boosting electronic transmission in MIL-88B-NH2(V1Fe5), was revealed by its band structure, transient photocurrent, electrochemical impedance spectroscopy, and scavenger quenching experiments. The enhancement of photocatalytic bactericidal performance of Fe-MOFs by V-ion-doping was confirmed by two other Fe-MOFs, MIL-53-NH2(V1Fe5) and MIL-101-NH2(V1Fe5), with the same metal ions and ligands, both of which have higher performance than the corresponding undoped MOFs. Among them, MIL-88B-NH2(V1Fe5) exhibits the highest photocatalytic bactericidal activity due to its suitable metal clusters ([M(mu 3-O)] cluster) and topological structure (three-dimensional rhomboid network structure). This work demonstrated the amplification effect of V ion doping on electron transport in Fe-MOFs photocatalysts.

Photothermal catalytic carbon dioxide (CO2) reduction has attracted increasing research attention as a promising method for recycling CO2 and producing renewable energy. However, it remains a challenge in the improvement of catalytic activity with regulated product selectivity in view of practical applications. Herein, we develop the two-dimensional layered V2C MXene (VC) supported Ni nanoparticle and NiO nanosheet (Ni@NiO/VC) composite as an efficient catalyst for selective photothermal reduction of CO2 to CH4. The optimal 0.8Ni@NiO/VC catalyst exhibits 48.1% of CO2 conversion with an evolution rate of 33.2 mmol·gcat−1·h−1 and 99.2% selectivity for CH4 production under a 300 W full-arc xenon lamp irradiation. Moreover, a long term of cyclic photothermal CO2 reduction reaction demonstrates the excellent stability of 0.8Ni@NiO/VC. The enhanced photothermal CO2 reduction activity with a high CH4 selectivity could be attributed to the large specific surface area and excellent photothermal effect of V2C MXene, and the synergistic effect of Ni and NiO on adsorption/activation of H2 and CO2 molecules. This work provides a feasible strategy for the construction of efficient photothermal CO2 reduction catalyst by properly incorporating transition metal nanoparticles and metal oxide with a suitable MXene.

Photocatalytic overall water splitting is an ideal green technology to produce the clean and renewable hydrogen energy. Herein, high crystalline zigzag GaN nanowires (NWs) are successfully synthesized through an Au -catalyzed chemical vapor deposition process. The single-crystalline zigzag nanowire is a polar-surface -dominated nanostructure composed of Ga and N atoms alternately as a result of the inherent surface atomic termination and polar charges. Compared with the non-polar-dominated smooth-surfaced nanowires, the zigzag nanowires attain multifold H2 and O2 evolutions in the presence of respective sacrificial reagents. More importantly, the zigzag nanowires realize the stoichiometric overall pure water splitting, due to the synergistic effect of the internal electric field between Ga-terminated and N-terminated facets that drives the spatial charge separation, the high charge mobility and polar surface energy. This work suggests that constructing polar surface on one-dimensional nanomaterial with spatially separated H2 and O2 evolution sites could be employed as a new crystal engineering strategy for designing efficient photocatalysts towards overall water splitting.

Artificial photosynthesis is a promising strategy for converting carbon dioxide (CO 2 ) and water (H 2 O) into fuels and value-added chemical products. However, photocatalysts usually suffered from low activity and product selectivity due to the sluggish dynamic transfer of photoexcited charge carriers. Herein, we describe anchoring of Ag single atoms on hollow porous polygonal C 3 N 4 nanotubes (PCN) to form the photocatalyst Ag 1 @PCN with Ag−N 3 coordination for CO 2 photoreduction using H 2 O as the reductant. The as-synthesized Ag 1 @PCN exhibits a high CO production rate of 0.32 μmol h −1 (mass of catalyst: 2 mg), a high selectivity (>94 %), and an excellent stability in the long term. Experiments and density functional theory (DFT) reveal that the strong metal–support interactions (Ag−N 3 ) favor *CO 2 adsorption, *COOH generation and desorption, and accelerate dynamic transfer of photoexcited charge carriers between C 3 N 4 and Ag single atoms, thereby accounting for the enhanced CO 2 photoreduction activity with a high CO selectivity. This work provides a deep insight into the important role of strong metal–support interactions in enhancing the photoactivity and CO selectivity of CO 2 photoreduction.

30% FeCN/ZIS (30% Fe doped g-C3N4 composited ZnIn2S4) was synthesized by a simple water bath method, via in-situ growth of abundant well-dispersed ZnIn2S4 nanosheets on the Fe doped g-C3N4 surface. Experimental results showed the optimized 30% FeCN/ZIS achieved the best photoreduction of Cr(VI) performance within a wide pH range, which was 9.5 times and 700 times higher than that of pure ZnIn2S4 and 30% FeCN (Fe doped g-C3N4). This is due to the intense synergy between the Fe-Nx bond and close interface contact produces a high-speed charge transfer channel, thus significantly improving the efficiency of optical carrier separation and migration. Meanwhile, UV-vis diffuse reflection spectra and photoluminescence spectroscopy showed that iron doping significantly narrowed the bandgap of g-C3N4, preventing electron-hole pair recombination. Further, the microstructures and charge separation properties were analyzed by scanning electron microscope, Photoluminescence Spectroscopy and time-resolved photoluminescence, which revealed the structure-activity relationship of composite structure and the synergistic mechanism of each functional component. This research should provide a viable technique for creating composites with high photocatalytic activity for the treatment of chromium-containing wastewater.

Developing new techniques toward low-cost, high-efficiency, and environmental-friendly transformation of alcohol to hydrocarbon compounds via carbon-carbon coupling has been paid a lot of research attention. In this study, we report for the first time on photothermal alcohol dehydration over a plasmonic W18O49 nanostructure under visible-to-near-infrared (Vis-NIR) irradiation. In the case of methanol dehydration, dimethyl ether and ethylene are generated as the major products with a 75% of methanol conversion efficiency. The light source, especially the NIR part, plays an important role in activation of the target methanol molecules, favoring the photothermal catalysis for both the methanol conversion and ethylene selectivity. The methanol dehydration activity is also greatly improved with increasing the content of W5+ in the surface of W18O49. More importantly, the non-stoichiometric W18O49 catalyst can be self-remediated via the reduction of surface W6+ to W5+ by photoelectron and methanol. In addition to methanol dehydration, the W18O49 catalyst also exhibits an extremely high catalytic activity for photothermal ethanol dehydration with nearly 98% ethanol conversion and 100% ethylene selectivity under Vis-NIR irradiation. This work provides a new insight into the photothermal catalytic alcohol dehydration over plasmonic semiconductors.

Zn vacancy ZnIn2S4tuned Gibbs free energy of *COOH which is the rate determining step of phototcatalytic CO2reduction from endothermic to exothermic process.

Modifying the polymeric carbon nitride (CN) with organic molecules is a promising strategy to enhance the photocatalytic activity. However, most previously reported works show that interchain embedding and edge grafting of the organic molecule can hardly be achieved simultaneously. Herein, we successfully synthesized organic molecule bifunctionalized CN (MBCN) through copolymerization of melon and sulfanilamide at a purposely elevated temperature of 550 °C. In MBCN, the edge grafted and interchain embedded benzene rings act as the electron-donating group and charge-transfer channel, respectively, rendering efficient photocatalytic H2 O2 production. The optimal MBCN exhibits a significantly improved non-sacrificial photocatalytic H2 O2 generation rate (54.0 μmol g-1  h-1 ) from pure water, which is 10.4 times that of pristine CN. Experimental and density functional theory (DFT) calculation results reveal that the enhanced H2 O2 production activity of MBCN is mainly attributed to the improved photogenerated charge separation/transfer and decreased formation energy barrier (▵G) from O2- to the intermediate 1,4-endoperoxide (⋅OOH). This work suggests that simultaneous formation of electron donating group and charge transfer channel via organic molecule bifunctionalization is a feasible strategy for boosting the photocatalytic activity of CN.