摘要：Nonprecious metal-based oxygen reduction reaction(ORR)electrocatalysts with high efficiency in both alkaline and acidic media are being intensively studied for the purpose of replacing expensive Pt-based catalysts;however,it is still a challenge to achieve superior ORR performances,especially in acidic ***,by pyrolysis of mixed precursors of diammonium phosphate,melamine and hemin,we prepared a nanocomposite catalyst(denoted as FeP@PGL)composed of nitrogen-doped carbon nanosheets with embedded FeP nanoparticles(NPs),which were encapsulated by in-situ formed phosphorus-doped graphene *** is found that phosphorous was preferentially doped in the coating layers on FeP NPs,instead of in the carbon *** FeP@PGL catalyst exhibited excellent ORR performance,with the onset and half-wave potential up to 1.01 and 0.90 V *** reversible hydrogen electrode(RHE)in alkaline media,and0.95 and 0.81 V *** in acidic media,*** thorough microscopy and spectroscopy characterizations,the interfacial charge transfer between the encapsulated FeP NPs and P-doped graphene layers was identified,and the local work function of the catalyst surface was also reduced by the interfacial *** interfacial synergy between the encapsulated FeP and phosphorus-doped graphene layers was essential to enhance the ORR *** study not only demonstrates the promising ORR properties of the encapsulated-FeP-based nanocomposite catalyst,but also provides direct evidence of the interfacial charge transfer effect and its role in ORR process.

摘要：The catalytic hydrogenation of halonitroarenes to haloanilines is a green and sustainable process for the production of key nitrogen-containing intermediates in fine chemical *** hydrogenation poses a significant challenge,which requires the rational design of the catalysts with proper hydrogenation ability for nitro group and simultaneously preventing dehalogenation of halogen ***,a highly effective Rh@Al_(2)O_(3)@C single-atom catalyst(SAC)was developed for the hydrogenation of m-chloronitrobenzene(m-CNB)to m-chloroaniline(m-CAN),through an in-situ grafting of metal during the assembly of MIL-53(Al),followed by confined *** characterizations reveal an exquisite structure of the Rh@Al_(2)O_(3)@C,containing atomically dispersed Rh sites onto Al_(2)O_(3) confined by the amorphous *** five-coordinated aluminum(Al^(Ⅴ))species are essential for achieving the atomic dispersion of Rh atoms,providing the unsaturated coordinative sites for *** to the benchmark Rh/γ-Al_(2)O_(3) and Rh/C nanocatalysts,the Rh@Al_(2)O_(3)@C SAC affords an excellent turnover frequency of 2317 molm-CNB·molRh^(–1)·h^(–1),the highest value to date in heterogeneous catalyst systems for the hydrogenation of m-CNB at 313 K and 20 bar H2,together with a sustained selectivity to m-CAN(~98%)during five consecutive *** superior catalytic performance of the Rh@Al_(2)O_(3)@C is attributed to a proper modulation of electronic structure of hydrogenation metal by forming SAC,together with an enhanced accessibility of acid function sites.