Modulation of electronic density states of carbon atom via multifaceted Cu doped Co2P particle for robust and efficient electrocatalytic hydrogen evolution reaction in aqueous acidic medium

Abstract

Development of Pt free catalyst for hydrogen evolution reaction (HER) having both superb efficiency and sound stability is a key challenge in the field of alternate fuel production. Herein, we have reported Cu doped multifaceted Co2P particles incorporated on expanded graphite synthesized via solvothermal method, and studied its catalytic activity. The composite catalyzes the evolution of H2 efficiently with a potential value 81 mV to achieve the benchmark current density of 10 mA cm-2 and a Tafel slope value of 113 mV dec‑1 coupled with a remarkable long-term stability for 21.6 h. Our experimental analysis provides strong evidence that the multifaceted Cu doped Co2P could work in concert with carbon atoms of the expanded graphite (EG) that leads in the changing of the energy states of nearby carbon atoms of the metal phosphide particle which is also in well agreement of our theoretical calculation. The lower contact electrical resistance of EG have significant impact in endowing fast electron transfer to the catalytic active sites and the aid of catalytic performance. The specific morphology of the catalyst hints at increased surface area and overall exposed active sites to bestow the catalytic performance. The study suggests that the energetically modulated carbon atoms can act as a fine active site for HER.