Developing an efficient photocatalyst,catalyzing formic acid(FA) dehydrogenation,can satisfy the demand of the H_(2) energy.Herein,a graphitic carbon nitride(gC_(x)N_(4))-based nanosheet(x=3.2,3.6 or 3.8) with melem r...Developing an efficient photocatalyst,catalyzing formic acid(FA) dehydrogenation,can satisfy the demand of the H_(2) energy.Herein,a graphitic carbon nitride(gC_(x)N_(4))-based nanosheet(x=3.2,3.6 or 3.8) with melem rings conjugated by Schiff-base bond(N=C-C=N) was synthesized,tuning the bandgaps(Eg) of graphitic carbon nitride(g-C_(3) N_(4)) in the range of 1.8 400 nm) without any additive at 25℃,which is the best value among ever-reported ones.This work provides a new strategy to boost dehydrogenation photocatalysis of FA,which will be promising for practical application of H2 in future energy field.展开更多
A 2 D-2 D titanium dioxide nanosheet-reduced graphene oxide(TNS-r GO)composite with better electronic conductivity and hydrophilicity was prepared by the hydrothermal method.The as-obtained TNS-r GO composite was furt...A 2 D-2 D titanium dioxide nanosheet-reduced graphene oxide(TNS-r GO)composite with better electronic conductivity and hydrophilicity was prepared by the hydrothermal method.The as-obtained TNS-r GO composite was further functionalized with 3-aminopropyltriethoxysilane(APTES)to provide a large amount of-NH2 groups on the surface for anchoring ultrafine Pd Ag alloy nanoparticles with an average particle size of 1.69 nm by a facile wet reduction approach.Benefiting from the combined effects of well-dispersed Pd Ag alloy nanoparticles,facilitated electron transfer from TNS-r GO to Pd,and increased electron density of active sites,the Pd8 Ag_(1)/NH_(2)-TNS-r GO catalyst exhibited excellent activity towards dehydrogenation of formic acid without adding any additives at 298 K,corresponding to an initial turn over frequency as high as 1090 h-1,which is much higher than that of most other state-of-theart catalysts.展开更多
The present work,in which cellulose isolated from formic acid fractionation(FAC)is decorated with polyetherimide(PEI)to attain highly efficient cellulose-derived PdAgbimetallic catalyst(PdAg-PEI-FAC),has been investig...The present work,in which cellulose isolated from formic acid fractionation(FAC)is decorated with polyetherimide(PEI)to attain highly efficient cellulose-derived PdAgbimetallic catalyst(PdAg-PEI-FAC),has been investigated,and the catalyst properties are characterized by XRD,XPS,BET,ICP-AES and HAADF-STEM.The as-obtained Pd_(3.75)Ag_(3.75)-PEI-FAC exhibits excellent catalytic performance for H_(2)evolution from a sodium formate-free formic acid(FA)aqueous medium at ambient temperature and the turnover frequency(TOF)reaches a high value of 2875 h^(-1)which is superior to most of the previously reported Pd-based heterogeneous catalysts supported on a carbon matrix in the literature.The remarkable catalytic activities of PdAg-PEI-FAC result from high dispersion Pd and synergistic effects between the PdAg bimetallic system.Furthermore,the amide(-NH)group in PEI coated on cellulose acting as a proton scavenger efficiently improves the catalytic property of catalyst.In addition,the critical factors affecting H;release,such as FA concentration,reaction temperature,PdAg compositions and support matrix type,are also evaluated.Based on the experimental results,the probable three-step mechanism of H_(2)evolution from FA over Pd_(3.75)Ag_(3.75)-PEI-FAC is proposed.In the end,the activation energy(Ea)of Pd_(3.75)Ag_(3.75)-PEI-FAC catalyst is calculated to 53.97 kJ mol^(-1),and this catalyst shows unique robustness and satisfactory re-usability with no loss of catalytic activity after five recycles.The findings in this work provide a novel routine from lignocellulose fractionation towards cellulose-derived catalyst for H_(2)evolution.展开更多
PdAg/Al_(2)O_(3) were pretreated by CO and H2 reduction pretreatments,respectively.The reduced catalysts were tested for HCHO and CO oxidation and characterized by Brunner Emmet Teller(BET),X-ray diffraction(XRD),tran...PdAg/Al_(2)O_(3) were pretreated by CO and H2 reduction pretreatments,respectively.The reduced catalysts were tested for HCHO and CO oxidation and characterized by Brunner Emmet Teller(BET),X-ray diffraction(XRD),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS)and oxygen temperature programmed desorption(O_(2)-TPD).These results indicate that the pretreatments have effect on PdAg reconstruction,PdAg particle size and active oxygen species,which are responsible for the catalytic performance.Compared with H2 reduction method,CO reduction is more suitable for PdAg/Al_(2)O_(3) pretreatment.PdAg/Al_(2)O_(3)-CO exhibited better catalytic performance.展开更多
Pd and Pd alloy membranes are of increasing interest for hydrogen separation and purification due to their good thermal stability, high permeability and perfect selectivity. PdCu alloy (60wt% Pd) membranes have simila...Pd and Pd alloy membranes are of increasing interest for hydrogen separation and purification due to their good thermal stability, high permeability and perfect selectivity. PdCu alloy (60wt% Pd) membranes have similar hydrogen permeability compared with PdAg alloy; meanwhile, it is cheaper than PdAg alloy. Furthermore, it has been reported that PdCu membrane has better resistance to poisoning and deactivation by H 2 S impurity. This paper reviews the properties and manufacturing methods of PdCu alloy membrane, finally, introduced some achievement made by us on PdCu alloy membrane.展开更多
Efficient and stable Pt-free electrocatalysts for oxygen reduction reaction(ORR)are indispensable for future fuel cells.Herein,we describe a heterostructure of Pd nanocrystals(PdNCs)on N-doped Ag nanowires(NWs)synthes...Efficient and stable Pt-free electrocatalysts for oxygen reduction reaction(ORR)are indispensable for future fuel cells.Herein,we describe a heterostructure of Pd nanocrystals(PdNCs)on N-doped Ag nanowires(NWs)synthesized using a direct epitaxial growth strategy with a Pd loading of only 9.5 wt.%.The PdAg bimetallic heterostructure showed the highest mass activity among reported PdAg-based ORR electrocatalysts and exhibited excellent stability,with only a 1.5 mV decay in the half-wave potential even after 20000 cycles of continuous testing.The remarkably enhanced activity and durability can be attributed to the distinct advantages of the ultrasmall PdNCs,cocatalysts of N-doped AgNWs,and their heterointerfaces.This work reveals that the epitaxial growth of a heterostructure on a stable support is a promising strategy for promoting catalytic performance.展开更多
基金financially supported by Heilongjiang Science Foundation(No.LH2020B006)the National Natural Science Foundation of China(Nos.51871078,21871221 and 21602175)+1 种基金the Fundamental Research Funds for the Central Universities(No.3102017jc01001)Start-Up Funding for Class D Talent of Xi’an University of Architecture and Technology(No.1608720038)。
文摘Developing an efficient photocatalyst,catalyzing formic acid(FA) dehydrogenation,can satisfy the demand of the H_(2) energy.Herein,a graphitic carbon nitride(gC_(x)N_(4))-based nanosheet(x=3.2,3.6 or 3.8) with melem rings conjugated by Schiff-base bond(N=C-C=N) was synthesized,tuning the bandgaps(Eg) of graphitic carbon nitride(g-C_(3) N_(4)) in the range of 1.8 400 nm) without any additive at 25℃,which is the best value among ever-reported ones.This work provides a new strategy to boost dehydrogenation photocatalysis of FA,which will be promising for practical application of H2 in future energy field.
基金the financial supports from the Shandong Provincial Natural Science Foundation(Grant No.ZR201910220216)the Key Research and Development Plan of Shandong Province(2019GGX104034)+1 种基金the Foundation of State Key Laboratory of High-efficiency Utilization of Coal,and Green Chemical Engineering(Grant No.2020-KF-18)the Taishan Scholar Program of Shandong Province(No.ts201712045)。
文摘A 2 D-2 D titanium dioxide nanosheet-reduced graphene oxide(TNS-r GO)composite with better electronic conductivity and hydrophilicity was prepared by the hydrothermal method.The as-obtained TNS-r GO composite was further functionalized with 3-aminopropyltriethoxysilane(APTES)to provide a large amount of-NH2 groups on the surface for anchoring ultrafine Pd Ag alloy nanoparticles with an average particle size of 1.69 nm by a facile wet reduction approach.Benefiting from the combined effects of well-dispersed Pd Ag alloy nanoparticles,facilitated electron transfer from TNS-r GO to Pd,and increased electron density of active sites,the Pd8 Ag_(1)/NH_(2)-TNS-r GO catalyst exhibited excellent activity towards dehydrogenation of formic acid without adding any additives at 298 K,corresponding to an initial turn over frequency as high as 1090 h-1,which is much higher than that of most other state-of-theart catalysts.
基金financially funded by the National Natural Science Foundation of China(NSFC,21476016,21776009)Fundamental Research Funds for the Central Universitiesthe special project for the construction of innovative province in Hunan Province of China(2019NK2031-3)
文摘The present work,in which cellulose isolated from formic acid fractionation(FAC)is decorated with polyetherimide(PEI)to attain highly efficient cellulose-derived PdAgbimetallic catalyst(PdAg-PEI-FAC),has been investigated,and the catalyst properties are characterized by XRD,XPS,BET,ICP-AES and HAADF-STEM.The as-obtained Pd_(3.75)Ag_(3.75)-PEI-FAC exhibits excellent catalytic performance for H_(2)evolution from a sodium formate-free formic acid(FA)aqueous medium at ambient temperature and the turnover frequency(TOF)reaches a high value of 2875 h^(-1)which is superior to most of the previously reported Pd-based heterogeneous catalysts supported on a carbon matrix in the literature.The remarkable catalytic activities of PdAg-PEI-FAC result from high dispersion Pd and synergistic effects between the PdAg bimetallic system.Furthermore,the amide(-NH)group in PEI coated on cellulose acting as a proton scavenger efficiently improves the catalytic property of catalyst.In addition,the critical factors affecting H;release,such as FA concentration,reaction temperature,PdAg compositions and support matrix type,are also evaluated.Based on the experimental results,the probable three-step mechanism of H_(2)evolution from FA over Pd_(3.75)Ag_(3.75)-PEI-FAC is proposed.In the end,the activation energy(Ea)of Pd_(3.75)Ag_(3.75)-PEI-FAC catalyst is calculated to 53.97 kJ mol^(-1),and this catalyst shows unique robustness and satisfactory re-usability with no loss of catalytic activity after five recycles.The findings in this work provide a novel routine from lignocellulose fractionation towards cellulose-derived catalyst for H_(2)evolution.
基金financially supported by the National Natural Science Foundation of China (No.21806011)
文摘PdAg/Al_(2)O_(3) were pretreated by CO and H2 reduction pretreatments,respectively.The reduced catalysts were tested for HCHO and CO oxidation and characterized by Brunner Emmet Teller(BET),X-ray diffraction(XRD),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS)and oxygen temperature programmed desorption(O_(2)-TPD).These results indicate that the pretreatments have effect on PdAg reconstruction,PdAg particle size and active oxygen species,which are responsible for the catalytic performance.Compared with H2 reduction method,CO reduction is more suitable for PdAg/Al_(2)O_(3) pretreatment.PdAg/Al_(2)O_(3)-CO exhibited better catalytic performance.
文摘Pd and Pd alloy membranes are of increasing interest for hydrogen separation and purification due to their good thermal stability, high permeability and perfect selectivity. PdCu alloy (60wt% Pd) membranes have similar hydrogen permeability compared with PdAg alloy; meanwhile, it is cheaper than PdAg alloy. Furthermore, it has been reported that PdCu membrane has better resistance to poisoning and deactivation by H 2 S impurity. This paper reviews the properties and manufacturing methods of PdCu alloy membrane, finally, introduced some achievement made by us on PdCu alloy membrane.
基金financial support from the National Natural Science Foundation of China(22379078).
文摘Efficient and stable Pt-free electrocatalysts for oxygen reduction reaction(ORR)are indispensable for future fuel cells.Herein,we describe a heterostructure of Pd nanocrystals(PdNCs)on N-doped Ag nanowires(NWs)synthesized using a direct epitaxial growth strategy with a Pd loading of only 9.5 wt.%.The PdAg bimetallic heterostructure showed the highest mass activity among reported PdAg-based ORR electrocatalysts and exhibited excellent stability,with only a 1.5 mV decay in the half-wave potential even after 20000 cycles of continuous testing.The remarkably enhanced activity and durability can be attributed to the distinct advantages of the ultrasmall PdNCs,cocatalysts of N-doped AgNWs,and their heterointerfaces.This work reveals that the epitaxial growth of a heterostructure on a stable support is a promising strategy for promoting catalytic performance.
