Strain and interfacial engineering to accelerate hydrogen evolution reaction of two-dimensional phosphorus carbide*

Hydrogen, regarded as a promising energy carrier to alleviate the current energy crisis, can be generated from hydrogen evolution reaction (HER), whereas its efficiency is impeded by the activity of catalysts. Herein, effective strategies, such as strain and interfacial engineering, are imposed to tune the catalysis performance of novel two-dimensional (2D) phosphorus carbide (PC) layers using first-principle calculations. The findings show that P site in pristine monolayer PC (ML-PC) exhibits higher HER performance than C site. Intriguingly, constructing bilayer PC sheet (BL-PC) can change the coordinate configuration of P atom to form 3-coordination-P atom (3-co-P) and 4-coordination-P atom (4-co-P), and the original activity of 3-co-P site is higher than the 4-co-P site. When an external compressive strain is applied, the activity of the 4-co-P site is enhanced whereas the external strain can barely affect that of 3-co-P site. Interestingly, the graphene substrate enhances the overall activity of the BL-PC because the graphene substrate optimizes the Δ G H* value of 4-co-P site, although it can barely affect the HER activity of 3-co-P site and ML-PC. The desirable properties render 2D PC-based material promising candidates for HER catalysts and shed light on the wide utilization in electrocatalysis.