Fabrication of Stable Ru-Doped Ni0.95Se Nanostructures for Photovoltaic Coupled Electrochemical Water Splitting in Alkaline Medium.

Abstract

Development of a competent and stable electrocatalyst coupled with photovoltaic system for the generation of green hydrogen, can be a plausible answer to the existing energy crisis. Herein, we have developed Ru doped Ni0.95Se via hydrothermal method as a bifunctional catalyst for overall water splitting coupled with photovoltaic system. The developed pristine and doped samples were thoroughly characterized by various techniques. The pristine Ni0.95Se and the optimized Ru0.1Ni0.95Se system required a potential of -0.470 and -0.318 V vs. RHE, respectively to acquire a current density of 50 mA cm-2 for HER. The rapid kinetics of the optimized Ru0.1Ni0.95Se is illustrated by the Tafel slope wherein the pristine Ni0.95Se has a Tafel slope value of 172.2 mV/dec, and the Ru0.1Ni0.95Se catalyst has 102 mV/dec. The bifunctional electrocatalyst of Ru0.1Ni0.95Se exhibits very high stability (7 days) in an alkaline medium. Density functional calculations show Ru0.1Ni0.95Se has -0.69  value indicating its remarkable stability. To improve the overall activity and stability of the electrocatalyst Ru dopant is introduced as it tunes the electronic environment by generating a synergistic effect between the metal ions and Se2- anions. This work provides an approach for the generation of green hydrogen through water electrolysis coupled with PV.