Advanced oxidation via the synergy of C-defective/C-O band modified ultrathin porous g-C_(3)N_(4)and PMS for efficient photothermal degradation of bisphenol pollutants and lignin derivatives

This work uses thermal polymerization of urea nitrate,oxyacetic acid and urea as the raw material to prepare ultra-thin porous carbon nitride with carbon defects and C-O band(OA-UN-CN).Density functional theory(DFT)calculations showed OA-UN-CN had narrower band gap,faster electron transport and a new internal construction electric field.Additionally,the prepared OA-UN-CN significantly enhanced photocatalytic activation of peroxymonosulfate(PMS)due to enhanced light absorption performance and faster electron overflow.As the result,the OA-UN-CN/PMS could entirely degrade bisphenol A(BPA)within 30 min,where the photodegradation rate was 81.8 and 7.9 times higher than that of g-C_(3)N_(4)and OA-UN-CN,respectively.Beyond,the OA-UN-CN/PMS could likewise degrade other bisphenol pollutants and sodium lignosulfonate efficiently.We suggested possible photocatalytic degradation pathways accordingly and explored the toxicity of its degradation products.This work provides a new idea on the development of advanced photocatalytic oxidation processes for the treatment of bisphenol pollutants and lignin derivatives,via a metal-free photothermal-catalyst.

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.

Exploration of optimal reaction conditions on lactic acid production from glucose photoreforming over carbon nitride

Biomass valorization by photoreforming approach provides a promising and alternative strategy to generate value-added chemicals and fuels.In this work,we demonstrate the selective production of lactic acid from glu-cose photoreforming over pristine graphitic carbon nitride(g-C_(3) N_(4))photocatalyst.Control experiments screen the best condition for the highest yield of lactic acid,including modulating pH,catalyst loading,and reaction time.100%glucose conversion is achieved along with almost 100%lactic acid yield under the optimized con-dition.Density functional theory(DFT)calculations reveal that the rate-determining step(RDS)of the overall reaction on g-C_(3) N_(4) is the conversion of pyruvaldehyde,where an electron transfer takes place.This present work provides experimental insights and theoretical understanding for selective lactic acid production from biomass photoreforming.

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.

浓H3PO4联合H2O2预处理能源植物地肤的性能研究

采用H3PO4联合H2O2(简称PHP)预处理地肤,基于木质素、半纤维素去除率、纤维素回收率、酶水解率等,研究温度、时间、H3PO4与H2O2浓度配比对预处理效果的影响。结果表明:提升预处理温度、时间和H3PO4浓度配比对半纤维素和木质素去除率有明显的促进作用,半纤维素和木质素去除率最大可达100.0%和90.7%,但也会加剧纤维素的损失。过高的H3PO4浓度配比(≥70%)不利于半纤维素和木质素去除。除10℃外,其他条件下,酶水解率差异不显著(>90%),但过高强度会导致一定程度的水解速率下降。

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.

LnVO_(4)(Ln=La,Ce,Pr,Nd,etc.)-based photocatalysts:Synthesis,design,and applications

LnVO_(4)(Ln=La,Ce,Pr,Nd,etc.)is an emerging photocatalyst for solving the energy and environmental crisis,due to its suitable band gap,special valence electronic structure,high thermal,and chemical sta-bility,as well as excellent photocatalytic performance.Although exhibiting great promise,the low solar power employment efficiency of LnVO_(4) materials has limited its further development and application.However,recent breakthroughs have been made in both heightening its photocatalysis efficiency and elu-cidating the essential photocatalytic mechanisms.Therefore,it is important to review and summarize recent research progress on LnVO_(4) nanomaterials and their applications.In this review,we systemat-ically report on and examine recent computational and experimental advances in the modification of LnVO_(4)-based photocatalysts through morphology adjustment,elemental doping,phase structure modula-tion,crystal facet modulation,defect modulation,heterostructure,and beyond.Thereafter,we outline cur-rent promising photocatalytic applications and discuss challenges/expected upcoming research aims for LnVO_(4)-based photocatalysts.Our goal is to furnish guidance for the reasonable design and preparation of highly efficient LnVO_(4)(Ln=La,Ce,Pr,Nd,etc.)-based photocatalytic materials for sundry applications.

Super-anti-freezing,tough and adhesive titanium carbide and L-ornithine-enhanced hydrogels

Hydrogels are highly porous three-dimensional crosslinked polymer networks consisting of hy-drophilic polymers,employed most practically in medicine and industry,often as biosensors.Simple hydrogels suffer limitations in their mechanical properties,such as tensile and com-pression,and freeze at sub-zero temperatures,which compromise their ability as useful biosen-sors.In this study,the incorporation of L-ornithine-based zwitterionic monomer(OZM),titanium carbide(MXene),and glycerol within polyacrylamide hydrogels was used to prepare a novel polyacrylamide/polyL-ornithine-based zwitterion/MXene(PAM/Porn/MXene)hydrogel to im-prove the mechanical,adhesion,and anti-freezing properties of pure polyacrylamide hydrogels.This study also analyzed the mechanical strength(tensile and compression),adhesion,and anti-freezing properties of a novel PAM/Porn/MXene hydrogel at 1%,4%,and 10%MXene concen-trations to establish to what extent the conductive MXene material enhanced these properties and concluded that the tensile and compressive properties improved linearly with the increase in the concentrations of MXene,adhesion decreased with the increased MXene concentrations,and syn-ergistic interaction between MXene and OZM significantly improved the anti-freezing properties up to-80°C.

Tailoring biochar by PHP towards the oxygenated functional groups(OFGs)-rich surface to improve adsorption performance

In this work,a modification method of H_(3)PO_(4)plus H_(2)O_(2)(PHP)was introduced to targetedly form abundant oxygenated functional groups(OFGs)on biochar,and methylene blue(MB)was employed as a model pollutant for adsorption to reflect the modification performance.Results indicated that parent biochars,especially derived from lower temperatures,substantially underwent oxidative modification by PHP,and OFGs were targetedly produced.Correspondingly,approximately 21.5-fold MB adsorption capacity was achieved by PHP-modified biochar comparing with its parent biochar.To evaluate the compatibility of PHP-modification,coefficient of variation(CV)based on MB adsorption capacity by the biochar from various precursors was calculated,in which the CV of PHP-modified biochars was 0.0038 comparing to0.64 of the corresponding parent biochars.These results suggested that the PHP method displayed the excellent feedstock compatibility on biochar modification.The maximum MB adsorption capacity was454.1 mg/g when the H_(3)PO_(4)and H_(2)O_(2)fraction in PHP were 65.2%and 7.0%;the modification was further intensified by promoting temperature and duration.Besides,average 94.5%H_(3)PO_(4)was recovered after 10-batch modification,implying 1.0 kg H_(3)PO_(4)(85%)in PHP can maximally modify 2.37 kg biochar.Overall,this work offered a novel method to tailor biochar towards OFGs-rich surface for efficient adsorption.

Will biomass be used for bioenergy or transportation biofuels? What drivers will influence biomass allocation

Potential competition for biomass for current and future bioenergy/biofuel uses in Brazil, Denmark,Sweden and the USA were compared. In each of these countries, bioenergy and biofuels are already important in their energy mix. However, there is limited competition for biomass between bioenergy(heat/power/residential/industrial) and transportation biofuel applications. This situation is likely to continue until advanced biofuel technology becomes much more commercially established. In each of these countries, biomass is predominantly used to produce bioenergy, even in those regions where biofuels are significant component of their transportation sector(Brazil,Sweden and USA). The vast majority of biofuel production continues to be based on sugar, starch and oil rich feedstocks, while bioenergyis produced almost exclusively from forest biomass with agricultural biomass having a small, but increasing, secondary role. Current and proposed commercial scale biomass-to-ethanol facilities almost exclusively use agriculture derived residues(corn stover/wheat straw/sugarcane bagasse). Competition for biomass feedstocks for bioenergy/biofuel applications, is most likely to occur for agricultural biomass with coproduct lignin and other residues used to concomitantly produce heat and electricity on site at biofuel production facilities.