Dual-functional marigold-like Zn_(x)Cd_(1-x)S homojunction for selective glucose photoreforming with remarkable H_(2)coproduction

The global commitment to pivoting to sustainable energy and products calls for technology development to utilize solar energy for hydrogen(H_(2))and value-added chemicals production by biomass photoreforming.Herein,a novel dual-functional marigold-like Zn_(x)Cd_(1-x)S homojunction has been the production of lactic acid with high-yield and H_(2)with high-efficiency by selective glucose photoreforming.The optimized Zn_(0.3)Cd_(0.7)S exhibits outstanding H_(2)generation(13.64 mmol h^(-1)g^(-1)),glucose conversion(96.40%),and lactic acid yield(76.80%),over 272.80 and 19.21 times higher than that of bare ZnS(0.05 mmol h^(-1)g^(-1))and CdS(0.71 mmol h^(-1)g^(-1))in H_(2)generation,respectively.The marigold-like morphology provides abundant active sites and sufficient substrates accessibility for the photocatalyst,while the specific role of the homojunction formed by hexagonal wurtzite(WZ)and cubic zinc blende(ZB)in photoreforming biomass has been demonstrated by density functional theory(DFT)calculations.Glucose is converted to lactic acid on the WZ surface of Zn_(0.3)Cd_(0.7)S via the photoactive species·O_(2)^(-),while the H_(2)is evolved from protons(H^(+))in H_(2)O on the ZB surface of Zn_(0.3)Cd_(0.7)S.This work paves a promising road for the production of sustainable energy and products by integrating photocatalysis and biorefine.

Systematic study of H2 production from catalytic photoreforming of cellulose over Pt catalysts supported on TiO2

Hydrogen(H2)production from photocatalytic reforming of cellulose is a promising way for sustainable H2 to be generated.Herein,we report a systematic study of the photocatalytic reforming of cellulose over Pt/m-TiO2(i.e.mixed TiO2,80%of anatase and 20%of rutile)catalysts in water.The optimum operation condition was established by studying the effect of Pt loading,catalyst concentration,cellulose concentration and reaction temperature on the gas production rate of H2(r(H2))and CO2(r(CO2)),suggesting an optimum operation condition at 40°C with 1.0 g·L^-1of cellulose and 0.75 g·L^-1of 0.16-Pt/m-TiO2 catalyst(with 0.16 wt%Pt loadting)to achieve a relatively sound photocatalytic performance with rH2=9.95μmol·h^-1.It is also shown that although the photoreforming of cellulose was operated at a relatively mild condition(i.e.with an UV-A lamp irradiation at40°C in the aqueous system),a low loading of Pt at^0.16 wt%on m-TiO2 could promote the H2 production effectively.Additionally,by comparing the reaction order expressed from both r(H2)(a1)and r(CO2)(a2)with respect to cellulose and water,the possible mechanism of H2 production was proposed.

Carbon quantum dots modified TiO_(2) composites for hydrogen production and selective glucose photoreforming

Lignocellulosic biomass photoreforming is a promising and alternative strategy for both sustainable H_(2) production and biomass valorization with infinite solar energy.However,harsh reaction conditions(high alkalinity or toxic organic solvents),with low biomass conversion and selectivity are often reported in literature.In this work,we report glucose photoreforming for coproduction of H_(2) and arabinose with improved selectivity under neutral condition using carbon quantum dots(CQDs)modified TiO_(2) composites.We show that the conventional CQDs fabricated by a facile one-step hydrothermal process could be endowed with novel color changing property,due to the particle aggregation under the regulation of incident light.The as-fabricated CQDs/TiO_(2) composites with certain colored CQDs could greatly improve glucose to arabinose conversion selectivity(-75%)together with efficient hydrogen evolution(up to 2.43 mmolh^(-1)g^(-1))in water.The arabinose is produced via the direct C1-C2 α-scissions mechanism with reactive oxygen species of·O_(2)^(-) and·OH,as evidenced by ^(13)C labeled glucose and the electron spin-resonance(ESR)studies,respectively.This work not only sheds new lights on CQDs assisted photobiorefinery for biomass valorization and H_(2) coproduction,but also opens the door for rationale design of different colored CQDs and their potential applications for solar energy utilization in the noble-metal-free system.

Selective superoxide radical generation for glucose photoreforming into arabinose

Biomass photorefinery to produce fuels and valuable chemicals is a promising approach to alleviating the energy crisis and achieving carbon neutrality.However,precisely modulating the photocatalytic conversion of biomass into value-added chemicals is still challenging.Here we demonstrate a feasible strategy to selectively produce arabinose via oriented glucose oxidation to gluconic acid,followed by the decarboxylation process for C1-C2 bond cleavage.To realize this process,gold nanoparticles(Au NPs)modified carbon nitride(AuCN)is rationally designed to regulate the electron transfer behavior of pristine carbon nitride from a two-electron pathway to a single-electron pathway.This allows selective production of superoxide(·O_(2)^(-))from oxygen reduction reaction which triggers glucose oxidation into gluconic acid.In addition,the arabinose production is synergistically promoted by the improved charge separation efficiency and extended visible-light absorption via localized surface plasmon resonance(LSPR)of Au nanoparticles.This work demonstrates an example of a mechanism-guided catalyst design to improve biofuels/chemicals production from biomass photorefinery.

A Unifi ed View of Carbon Neutrality:Solar-Driven Selective Upcycling of Waste Plastics

With the rapid development of plastic production and consumption globally,the amount of post-consumer plastic waste has reached levels that have posed environmental threats.Considering the substantial CO_(2)emissions throughout the plastic lifecycle from material production to its disposal,photocatalysis is considered a promising strategy for eff ective plastic recycling and upcycling.It can upgrade plastics into value-added products under mild conditions using solar energy,realizing zero carbon emissions.In this paper,we explain the basics of photocatalytic plastic reformation and underscores plastic feedstock reformation pathways into high-value-added products,including both degradation into CO_(2)followed by reformation and direct reformation into high-value-added products.Finally,the current applications of transforming plastic waste into fuels,chemicals,and carbon materials and the outlook on upcycling plastic waste by photocatalysis are presented,facilitating the realization of carbon neutrality and zero plastic waste.