Electron-distribution control via Pt/NC and MoC/NC dual junction:Boosted hydrogen electro-oxidation and theoretical study

The scarcity,high cost and susceptibility to CO of Platinum severely restrict its application in alkaline hydrogen oxidation reaction(HOR).Hybridizing Pt with other transition metals provides an effective strategy to modulate its catalytic HOR performance,but at the cost of mass activity due to the coverage of modifiers on Pt surface.Herein,we constructed dual junctions'Pt/nitrogen-doped carbon(Pt/NC)andδ-MoC/NC to modify electronic structure of Pt via interfacial electron transfer to acquire Pt-MoC@NC catalyst with electron-deficient Pt nanoparticles,simultaneously endowing it with high mass activity and durability of alkaline HOR.Moreover,the unique structure of Pt-MoC@NC endows Pt with a high COtolerance at 1,000 ppm CO/H_(2),a quality that commercial Pt-C catalyst lacks.The theoretical calculations not only confirm the diffusion of electrons from Pt/NC to Mo C/NC could occur,but also demonstrate the negative shift of Pt d-band center for the optimized binding energies of*H,*OH and CO.

High density iridium synergistic sites boosting CO-tolerate performance for PEMFC anode

The usage of cheap crude H2 in proton-exchange membrane fuel cells(PEMFCs)is still unrealistic to date,due to the suffering of the current Pt based nano-catalysts from impurities such as CO in anode.Recently,synergistic active sites between single atom(SA)and nanoparticle(NP)have been found to be promising for overcoming the poisoning problem.However,lengthening the nanoparticle-single atom(SA–NP)interface,i.e.,constructing high density synergistic active sites,remains highly challenging.Herein,we present a new strategy based on molecular fusion strategy to create abundant SA–NP interfaces,with high density SA–NP interfaces created on a two dimensional nitrogen doped carbon nanosheets(Ir-SACs&NPs/NC).Owing to the abundance of SA–NP interface sites,the catalyst was empowered with a high tolerance towards up to 1000ppm CO in H_(2) feed.These findings provide guidelines for the design and construction of active and anti-poisoning catalysts for PEMFC anode.

CO耐受的单位点/纳米颗粒协同型质子交换膜燃料电池阳极催化剂

Nanosized Pt catalysts are the catalyst-of-choice for proton exchange membrane fuel cell(PEMFC)anode,but are limited by their extreme sensitivity to CO in parts per million(ppm)level,thereby making the use of ultrapure H_(2)a prerequisite to ensure acceptable performance.Herein,we confront the CO poisoning issue by bringing the Ir/Rh single atom sites to synergistically working with their metallic counterparts.In presence of 1000 ppm CO,the catalyst represents not only undisturbed H_(2)oxidation reaction(HOR)catalytic behavior in electrochemical cell,but also unparalleled peak power density at 643 mW cm^(-2)in single cell,27-fold in mass activity of the best PtRu/C catalysts available.Pre-poisoning experiments and surface-enhanced Raman scattering spectroscopy(SERS)and calculation results in combine suggest the presence of adjacent Ir/Rh single atom sites(SASs)to the nanoparticles(NPs)as the origin for this prominent catalytic behavior.The single sites not only exhibit superb CO oxidation performance by themselves,but can also scavenge the CO adsorbed on approximated NPs via supplying reactive OH*species.We open up a new route here to conquer the formidable CO poisoning issue through single atom and nanoparticle synergistic catalysis,and pave the way towards a more robust PEMFC future.