Computational Investigation of Hydriding and Strain Effects on theBinding Energies of Electrochemical CO2RR and HER Intermediates

A two-step process, involving syngas production, has recently beensuggested as a feasible strategy for resolving the limit to the selectivity that can beachieved by fuel production via the electrochemical carbon dioxide reduction reaction(CO2RR). In pursuit offinding the optimal phase, orientation, and strain conditions ofa Pd substrate for syngas production, we investigate the effects of hydriding and strainon the binding energies (BEs) of CO2RR and hydrogen evolution reactionintermediates on the (111), (100), and (110) surfaces of Pd by using densityfunctional theory calculations. The calculation results show that the BEs are weakenedby hydriding, most significantly on the (111) surface, rendering it more energeticallyfavorable for syngas production than the others at sufficiently negative potentials. It isalso shown that PdH(100) can be more energetically favorable than PdH(111) undercompressive strains at weakly negative potentials owing to the high strainsusceptibilities of the*CO BEs on the surface. These results are explained in termsof the effects of hydriding and strain on the electronic structures of Pd surface atoms and adsorption-induced mechanicalinteractions.

Automated summary

A two-step process involving syngas production has been suggested as a feasible strategy to overcome the limit to selectivity in fuel production via CO2RR. By studying the effects of hydriding and strain on the binding energies of Pd surfaces, it is found that the Pd (111) surface is energetically more favorable for syngas production under negative potentials. Additionally, compressive strains can make PdH(100) more energetically favorable than PdH(111) at weakly negative potentials.