Efficient carbon monoxide electroreduction on two-dimensional transition metal phosphides: A computational study

Carbon monoxide electroreudction (COER) has been emerging as a key component for tandem carbon dioxide (CO2) electrolysis, in which engineering COER electrocatalysts with good catalytic performance is still a huge challenge. In this work, we performed comprehensive density functional theory (DFT) computations to explore the feasibility of a new class of two-dimensional transition metal phosphides (TM2P) as COER catalysts. Our simulations demonstrated that these TM2P candidates possess rather high stability and excellent electrical conductivity. Remarkably, Nb2P monolayer was revealed to exhibit high COER catalytic activity for CH4 production due to its small limiting potential (−0.51 V) from the CH3⁎ hydrogenation step. Interestingly, Nb2P monolayer was predicted to exhibit highest COER catalytic activity among these TM2P candidates due to its moderate interaction with CH3⁎ intermediate, which may be attributed to its optimal d-band center in β-spin orbitals. Our work not only enriches the applications of 2D metal phosphides, but also offers an in-deep insight into the rational design of efficient COER catalysts.