B-Doped Penta-Graphene as a Metal-Free Electroreduction Catalyst for CO Reduction: A DFT Study

The efficient catalytic transformation of C1 compounds is a research hotspot and difficulty at this stage. In this paper, a new metal-free catalyst for B-doped penta-graphene (B@PG) was designed by DFT calculations for the efficient electrocatalytic reduction of CO. Two doping configurations, B(sp2)@PG and B(sp3)@PG, were systematically investigated. The formation energies indicate that both doped structures are metastable and that their preparation requires special treatment, while molecular dynamics simulations confirm their thermal (dynamical) stability at high temperature. Boron doping narrows the band gap of penta-graphene, which may facilitate charge-transfer processes in electrocatalysis. CO is chemisorbed on the penta-graphene surface, and boron doping further strengthens CO adsorption. On pristine penta-graphene, CO is reduced to a mixture of CH3OH and CH4, making selective control difficult. B(sp2)@PG also produces mixed products and suffers from the accumulation of strongly bound intermediates. In contrast, B(sp3)@PG exhibits excellent selectivity toward CH4, which is preferentially produced via *CH3O intermediate with a low limiting potential (−0.29 V), while CH3OH formation is highly unfavorable. The competing hydrogen evolution reaction is not thermodynamically suppressed at the working potential; the high CH4 selectivity originates from the favorable free-energy landscape of the *CH3O intermediate pathway. This work provides new theoretical insights into the metal-free catalyst design and the efficient conversion of CO.