Catalytic hydrodeoxygenation (HDO) of aromatic aldehydes represents a core research direction in the efficient utilization of lignin. In this study, a cost-effective catalyst was constructed by incorporating rich lattice defects into Ni nanoparticles. The catalyst was synthesized via a uniform precipitation method, employing urea as the precipitant. By introducing aluminum nitrate during the precipitation process, nickel was effectively segregated to inhibit its growth and the generation of well-crystallized, defect-free Ni nanoparticles, thereby generating a substantial quantity of defective Ni nanoparticles with abundant lattice defects. The catalyst was characterized using XRD, TEM, HRTEM, EDS line and mapping scanning, XPS and H-2-TPD, confirming the formation of Ni nanoparticles with a narrow size distribution of similar to 5 nm with numerous lattice defects. The hydrodeoxygenation of vanillin was employed to evaluate the catalyst's activity, with investigations into the effects of Al content, solvents, temperature, H-2 pressure, and reaction time. The reaction was successfully conducted at 363 K in water. The catalyst demonstrated excellent hydrodeoxygenation activity across a series of other aromatic aldehyde compounds. Cycle experiments confirmed the catalyst's stability, maintaining its activity over at least five consecutive uses.

The regulation of metal-acid bifunctional sites is of great significance in heterogeneous catalysis. In this study, commercial Pt/Al2O3 catalysts were modified by ethyl iodide under reductive conditions to prepare I-Pt/Al2O3 catalysts with intimate metal-acid bifunctional sites for the selective hydrogenolysis of furfuryl alcohol to 1,2-pentanediol. Electron transfer from Pt nanoparticles to I results in the formation of a negatively charged I adatom on the positively charged Pt surface, which induces on-surface hydrogen spillover to form Pt(H-)-I(H+) metal-acid bifunctional sites under a hydrogen atmosphere. By modulating the I coverage, the ratio between metal and acid sites on the catalyst surface can be finely adjusted at the nanoscale, providing a tunable hydrogenolysis selectivity of th furan ring toward 1,2- or 1,5-pentanediol. The selectivity for 1,2-pentanediol was promoted from 17.2% over the initial Pt/Al2O3 catalyst to 67.0% over I-Pt/Al2O3 catalysts at full furfuryl alcohol conversion. The developed Pt-I catalyst with controllable metal-acid bifunctional sites holds great promise for the catalytic upgrading of biomass-derived molecules.

The selective hydrogenation of biomass-derived compounds is pivotal for the synthesis of high-value-added chemicals. The controllable hydrogenation in furfural for furfuryl alcohol or tetrahydrofurfuryl alcohol is highly desirable yet challenging. In this study, Ni2Al-LDO (layered double oxide) metal oxide catalyst featuring highly dispersed surface NiO was synthesized via a structural topological transformation using layered double hydroxides. The catalyst exhibited excellent performance in the hydrogenation of furfural, achieving 91.42% yield of furfuryl alcohol (FOL) at 160 °C and 1.4 MPa H2. Gradual reduction of Ni2Al-LDO produced Ni/NiO mixtures, enabling tunable shift from FOL to tetrahydrofurfuryl alcohol (HFOL) as the NiO content decreased and the Ni content increased. After a two-hour reduction at 700 °C, the HFOL yield reached 93.95%. CO2-TPD, NH3-TPD and FT-IR measurements revealed that variations in reduction degree on nickel influenced the adsorption behavior of furfural. NiO species could only adsorb the C=O group of furfural, isopropanol serves as the hydrogen source, and furfural undergoes hydrogenation to form furfuryl alcohol following the MPV conversion pathway. Whereas the flat adsorption mode on the metallic Ni surface facilitated the simultaneous adsorption and activation of both the furan ring and the carbonyl group of furfural. In addition, the hydrogen sources of the reaction systems also differ: the Ni2Al-LDO catalyst is only capable of activating isopropanol, with the reaction proceeding via the MPV mechanism; in contrast, Ni2Al-LDO-700 can activate both H2 and isopropanol, where H2 serves as the primary hydrogen source. This work elucidates a clear structure-activity relationship centered on the metal oxidation state and provides a practical reduction-engineering approach for designing adaptable catalysts in biomass upgrading.

The recycling and upgrading of polycarbonate (PC) plastic wastes have attracted worldwide attention, butthe selective cleavage of inert C-C bonds remains a key challenge. Herein, we show that a noble metal-freepotassium-modified covalent triazine-based framework (K-CTF), as a strong base catalyst, could efficientlycatalyze the cleavage of C-C bonds in various PC plastic wastes to achieve valuable phenolics. Comparedwith other alkali- and alkaline earth metal (Na, Mg, and Ca)-modified catalysts, K-CTF showed an optimalcatalytic performance due to its strong basicity. The total yield of acquired phenolic monomers reached upto 98.1%. The reaction pathway investigation displayed that PC plasticsfirstly underwent methanolysis toform the bisphenol A (BPA) intermediate. A catalytic amount of strong basic sites then promoted the clea-vage of C-C bonds to form phenol and 4-isopropenylphenol (IPP) by the deprotonation activation of thephenolic hydroxyl group in BPA. Thereinto, methanol and H2O played crucial parts in the PC plastic alcoholy-sis and C-C bond cleavage, respectively, which acted synergistically for the high-efficiency conversion of PCplastics to monophenols. This work opens new opportunities for the efficient utilization of PC plastic wastes.

Vanadium-based catalysts are widely used in the oxidation of carbohydrates to produce formic acid (FA), a promising liquid organic hydrogen carrier, but still suffers from low yield due to the formation of CO2. This study found that the spatially isolated VOx on active carbon (AC) can significantly increase FA yield from 43.5 to 72.9% in glucose oxidation compared with free VOx. Two specific roles of AC were revealed. Firstly, the oxygenated functional groups, high surface area and abundant microporous of AC, play a crucial role in the atomic dispersion of VOx, resulting in a heterogeneous, single-site VOx-AC catalyst. The isolated VOx site favors the oxidative C-C bond cleavage in glucose via a stepwise alpha-cleavage pathway, thus improving FA selectivity. Secondly, the conductive AC acts as an electron buffer, which accelerates the catalytic redox cycle between V5+ and V4+ of the isolated VOx sites, thus increasing the reaction activity. The prepared single-site VOx-AC catalyst is reusable and can generate a concentrated FA solution (4.7 wt%) by simple filtration of the solid catalyst. This work presents a simple method for the production of H2 energy carrier from biomass and provides a fundamental basis for designing efficient catalytic systems for aqueous-phase oxidation reactions.

A hydrogen bond regulation strategy with a Ni–Fe catalyst was developed to enhance cleavage of C–C bonds for the nearly complete transformation of polylactic acid plastic wastes in water into CO 2 and H 2 .

Polylactic acid (PLA) as a biodegradable plastic currently has the highest production among the global bio-based plastics. In comparison to the natural degradation of PLA with a substantial period of time, the development of a novel transformation process for the upcycling of PLA plastic into green H2 and CO2 using H2O is of great significance. Herein, a hydrogen bond regulation strategy with a Ni-Fe catalyst is proposed to achieve the direct transformation of PLA plastic wastes in H2O into CO2 and H2 at 310 degrees C. The fabricated Ni-Fe catalyst enables the cleavage of the intramolecular hydrogen bond in PLA-derived oxygenates to convert various PLA plastic wastes in H2O, and H2 production reaches up to 62.6 mmol gplastic-1 accompanied by a H2 selectivity of 93.5%. Further investigation of the reaction pathway reveals that, compared to the Ni catalyst, the incorporation of Fe into Ni greatly enhances the catalytic cleavage of intramolecular hydrogen bonds, which further accelerates C-C bond cleavage. And it displays tremendous hydrogen production capability over ten cycles. This approach provides an innovative solution for upgrading PLA wastes into sustainable hydrogen and contributes to a low-carbon future.

Cu-based catalysts are advantageous for selectively catalyzing the hydrogenation of the C=O bonds in furfural (FF). Nevertheless, debates are ongoing regarding the identification of active sites. FeCuxMg catalysts were prepared using a hydrotalcite precursor. During the early stages of the reaction, the selective hydrogenation activity of the C=O bond exhibited a volcano-shaped trend with increasing Cu content. FeCu0.15Mg showed the highest hydrogenation activity among all catalysts examined. In-situ X-ray diffraction (XRD), in-situ DRIFT, X-ray photoelectron spectroscopy (XPS) and other analytical techniques confirmed that Cu0-Cu delta+ sites assume a predominant role in catalytic reactions. At the optimal Cu/Fe ratio, the oxygen vacancies generated by FeOx facilitated the activation of the FF molecules. The highly dispersed Cu0-Cu delta+ sites served a crucial function in the activation of H2 and the rapid formation of reaction intermediates, significantly accelerating the reaction rate and process of FF hydrogenation.

As multifunctional platform molecules, α-keto acids and their esters hold significant value in pharmaceutical synthesis, functional materials, and metabolic processes. Conventional chemical synthesis routes for these compounds are well-established and efficient but often rely on precious metals, high-pressure conditions, and hazardous reagents, leading to considerable environmental costs. In contrast, catalytic biomass conversion pathways—utilizing renewable feedstocks under mild conditions—offer promising alternatives. However, issues such as catalyst deactivation and undesired side reactions remain to be addressed. This review systematically summarizes recent advances in both traditional chemical and catalytic biomass-based synthesis of α-keto acids and their esters, with a particular emphasis on green synthetic routes derived from renewable resources. Finally, current challenges and future perspectives in the field are briefly discussed.

5-Hydroxymethylfurfural (HMF), regarded as one of the top bio-based platform chemicals, possesses a molecular structure with C 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 O, C-OH, and a furan ring, allowing for its conversion into a variety of high value-added green chemicals through a range of catalytic reactions. This study focuses on the highly promising yet challenging conversion of HMF into furanic and non-furanic chemicals with tunable selectivity via hydrogenation/hydrogenolysis over cobalt-copper-aluminum layered double oxide (CoxCuAl LDO) catalysts. The synthesized CoxCuAl catalysts were meticulously characterized and then utilized for the efficient transformation of HMF into 2,5-bis(hydroxymethyl)furan (BHMF) and 1,2,6-hexanetriol (1,2,6-HTO). The CoAl, CuAl, and physically mixed CoAl + CuAl catalysts predominantly favored BHMF production via hydrogenation of HMF's carbonyl group. However, the optimal Co5CuAl catalyst achieved efficient and switchable production of BHMF (similar to 91% yield) or 1,2,6-HTO (similar to 72% yield) under tunable reaction conditions, owing to the synergistic effects of CoCu in modifying electronic-geometric properties, where the electron-enriched Co facilitated ring-opening hydrogenolysis. Indeed, the formed CoCu interface/alloy is capable of both hydrogenation and ring-opening hydrogenolysis, enabling adjustable product formation; however, the absence of this active site in monometallic catalysts hinders ring-opening hydrogenolysis, resulting in the production of a non-switchable product, BHMF. Density functional theory (DFT) calculations and experimental studies disclosed that the bimetallic catalyst outperformed its monometallic counterpart in terms of HMF and H adsorption, which can be attributed to the formation of the CoCu alloy, inducing a modified d-band center. The findings and future development of this work would lead to sustainable production of high value-added bio-diols/triols from bioresources.

Catalytic oxidative depolymerization of lignin is an important strategy for producing valuable oxygen-functionalized monoaromatic compounds. However, this process is less efficient over heterogeneous catalysts due to the slow rate-determining step of selective oxidation of secondary alcohol (C-alpha-OH to C-alpha=O) in beta-O-4 lignin linkages. Herein, a facile and efficient Ru(OH)(x)/C catalyst was developed for the oxidative depolymerization of lignin model compounds and real lignin in aqueous phase using molecular oxygen as oxidant. Extensive characterizations revealed that molecular oxygen abstracts electrons from the conductive carbon matrix to generate superoxide radicals (center dot O-2(-)), which are subsequently converted to hydroperoxide radicals (HOO center dot) in the presence of water. The C-alpha-OH in the beta-O-4 linkages first reacts with Ru-OH to form a Ru-O-C(H)- metal alkoxide intermediate, which then undergoes beta-H elimination with the help of HOO center dot to generate H2O2 and surface Ru-O-C center dot- species. Hydrolysis of Ru-O-C center dot- leads to the generation of C-alpha=O products and the regeneration of Ru-OH sites. Different from the traditional Ru(OH)(x)-catalyzed alcohol dehydration mechanism in which Ru abstracts beta-H to form Ru-H, in this case, the beta-H in the Ru-alkoxide intermediate is eliminated by the hydroperoxide radicals rather than Ru, avoiding the formation of inert Ru-H species, thereby accelerating the dehydrogenation of C-alpha-OH to C-alpha=O. Electrochemical measurements further confirmed the charge transfer from Ru(OH)(x) to carbon during alcohol oxidation, demonstrating that electron donation by alcohol occurs on Ru(OH)(x), while electron abstraction by O-2 occurs on the carbon. The free-radical-involved beta-H elimination reaction pathway endows Ru(OH)(x)/C with superior catalytic oxidation activity in the aqueous phase compared with traditional metal oxides supported Ru(OH)(x) (e.g. SiO2, Al2O3, TiO2), and provides a fundamental basis for the rational design of aqueous phase oxidation catalysts.

The selective oxidation of glycerol to valuable lactic acid (LA) is a typical cascade catalytic process in biomass conversion. The present study demonstrates that K addition into Pt/Sn-MFI can promote the selectivity in the selective oxidation of glycerol to LA, with glycerol conversion of 92.8% and LA selectivity of 86.2% in a base-free solution. Comprehensive experimental and characterization studies reveal that K+, not only acts as the electron donor for Pt nanoparticles, promoting the oxidation of secondary hydroxyl groups of glycerol to dihydroxyacetone (DHA), but also mediates the acid/base properties for Pt/Sn-MFI, facilitating the dehydration, 1,2-hydride shift and hydration of DHA to LA. This work not only presents an elegant showcase of achieving a synergistic effect by modulating the microenvironment but also provides a rational approach to enhance the catalytic performance in the selective oxidation of glycerol.

With the intensification of the global energy crisis, hydrogen has attracted significant attention as a high-energy-density and zero-emission clean energy source. Traditional hydrogen production methods are dependent on fossil fuels and simultaneously contribute to environmental pollution. The aqueous phase reforming (APR) of renewable biomass and its derivatives has emerged as a research hotspot in recent years due to its ability to produce green hydrogen in an environmentally friendly manner. This review provides an overview of the advancements in APR of lignocellulosic biomass as a sustainable and environmentally friendly method for hydrogen production. It focuses on the reaction pathways of various biomass feedstocks (such as glucose, cellulose, and lignin), as well as the types and performance of catalysts used in the APR process. Finally, the current challenges and future prospects in this field are briefly discussed.

Oxygen vacancies (OVs) play a crucial role in photocatalytic nitrogen fixation, yet current studies predominantly focus on preconstructed OVs (PC-OVs), with limited attention given to photoexcitation-induced OVs (PE-OVs). In this work, Sn-doped BiOCl-V-O (Sn-BOC-V-O) was synthesized via a facile one-pot hydrothermal method to actively generate PE-OVs. EPR analysis confirmed that Sn doping promotes the formation of PE-OVs. Quasi in situ XPS revealed that light irradiation further enhances OVs generation in Sn-BOC-V-O and induces electron transfer from the O and Bi to the Sn. Photoelectrochemical tests demonstrated that Sn-BOC-V-O improves visible-light absorption, facilitates charge separation, and suppresses carrier recombination, collectively leading to a 16.8-fold increase in the nitrogen fixation rate compared to BOC-V-O. In situ DRIFTS spectroscopy tracked key reaction intermediates, while DFT calculations indicated electron transfer from Sn-BOC-V-O to adsorbed N-2, highlighting the synergy between Sn and OVs in promoting N-2 activation and improving the photocatalytic nitrogen reduction reaction (pNRR) efficiency. Importantly, Sn-BOC-V-O exhibits a reduced energy barrier of 1.81 eV for the rate-determining step, which is significantly lower than that of BOC-V-O (2.22 eV), underscoring the critical role of Sn in optimizing reaction kinetics. This study offers insights into the design of photoexcited OV-active sites and emphasizes the dynamic role of OVs in catalytic reactions.

The catalytic conversion of biomass-derived 5-hydroxymethylfurfural (HMF) into high-value-added products, such as 2,5-bis(hydroxymethyl)furan (BHMF) and 2,5-bis(hydroxymethyl)tetrahydrofuran (BHMTHF) has attracted considerable attention. Among this process, controlling the distribution of the catalytic products plays a vital role. In this paper, NiCe and NiZnCe catalysts were prepared by the sol-gel method. By optimizing the metal loading amount and reaction conditions, a selectivity of 95.3 % to BHMTHF with the NiCe catalyst and a selectivity of 94.1 % to BHMF with the NiZn0.1Ce catalyst were achieved. Characterization results demonstrated that the addition of Zn causes electrons to transfer from Zn to Ni and increases the content of oxygen vacancies on the catalyst surface, inhibiting the adsorption of furan ring on the NiZn0.1Ce surface, thus precisely controlling hydrogenation sites at the C--O rather than the C--C of the furan ring. This study provides guides for precise regulation of product selectivity when designing catalysts, and it is expected to be applied to the catalytic conversion of biomass-derived platform molecules.

The hydrogenation of biomass-derived 5-hydroxymethylfurfural (HMF) to the value-added chemicals plays vital role in the development of renewable resources, while the precisely chemical regulation of products selectivity remains a great challenge. Herein, Zr-Beta based catalysts were fabricated with the controllable acid base sites for the selective hydrogenation of HMF. Importantly, the products selectivity could be facilely switched over Zr-Beta based catalysts: 100 % of 2,5-bis(isopropoxymethyl)furan (BPMF) selectivity was acquired over ZrBeta, whereas 99.4 % of 2,5-bis(hydroxymethyl)furan (BHMF) selectivity was achieved over K-Zr-Beta. The characterization analysis revealed that more Lewis acid sites in Zr-Beta facilitated Meerwein-Ponndorf-Verley (MPV) reduction of HMF and the further etherification of BHMF to acquire BPMF. However, the incorporation of K+ + into Zr-Beta could exchange with silanol protons and Zr(IV) sites, which resulted in the decrease of Lewis acid amount accompanied with the generation of base sites. Notably, the regulated acid and base sites in K-ZrBeta catalyst synergistically acted in the selective hydrogenation of HMF to BHMF. This work provides a feasible strategy for adjusting selectivity of HMF hydrogenation products by tuning the catalysts acid-base sites.

Glycerol, as the main byproduct in biodiesel production, is attractive for the synthesis of value-added chemicals with the rapid increase of the biodiesel market in recent years. In this study, we developed a bifunctional Au/Sn-Beta catalyst via a molecule linkage strategy for the one-pot catalytic conversion of glycerol to methyl lactate (MLA) with molecular oxygen as the oxidant. Bifunctional Au/Sn-Beta was constructed using beta-mercaptoethylamine as a linkage molecule to anchor negative Au species on the negative surface of Sn-Beta zeolites. beta-Mercaptoethylamine with a well-defined structure of head and tail functional groups was anchored on Sn-Beta zeolite through the interaction of amine groups with the framework Sn sites and weakly acidic silanols. Gold species with negative charge were captured by thiol groups of beta-mercaptoethylamine anchored on Sn-Beta. Upon calcination, highly dispersed Au nanoparticles (similar to 2 nm) were confined in the crystal of Sn-Beta zeolite, which was proved by Tomogram-section TEM images. Linkage molecules with different structures were employed. The role of the linkage molecule was revealed by XPS, FTIR, and Raman spectroscopy. It was observed that electrons were transferred from Au sites to Sn sites, which facilitated the dispersion and stabilization of Au sites. A yield of 79.3% to MLA with 100% of glycerol conversion was achieved over the prepared Au/Sn-Beta at 160 degrees C for 1.5 h, which was much higher than that over Au/Sn-Beta prepared by the wet impregnation method. The positive charge on Au sites decreased the catalytic oxidation ability of the catalyst. The catalyst showed good catalytic activity and stability in ten batch reaction runs.

A series of S-scheme heterojunctions, XCN@MoO3 (XCN@M, X = Cl, Br, I), were synthesized via a simple thermal polymerization, and the effect of halogen doping on construction of S-scheme heterojunctions was systematically explored. The ICN@M heterojunction showed exceptional photocatalytic performance, achieving 100 % degradation of 50 mg/L RhB in 90 min, 40.37 times and 2.34 times higher than pure g-C3N4 and CN@M, respectively. Notably, ICN@M outperformed CN@M and some other photocatalysts reported. DFT result revealed halogen doping reduced the work function of CN, proved the maximum work function difference of ICN@M and the formation of the strongest built-in electric field between the surface of MoO3 with an electron- rich region and the surface of ICN with a hole-rich region, thus facilitating electron transfer at the heterojunction interface, reducing recombination of photogenerated carriers and promoting the catalytic performance. Fukui function and frontier orbital theory identified a possible degradation pathway of RhB dominated by center dot O2- and 1O2 and the toxicity of final products during the photocatalysis degradation of RhB was evaluated. This work highlighted the importance of work function differences in designing photocatalyst heterostructures and offered a new option for environmental treatment.