NiWO₃ Nanoparticles Grown on Graphitic Carbon Nitride (g‐C₃N₄) Supported Toray Carbon as an Efficient Bifunctional Electrocatalyst for Oxygen and Hydrogen Evolution Reactions

Abstract

Catalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are at the heart of water oxidation reactions. Despite continuous efforts, the development of OER/HER electrocatalysts with high activity at low cost remains a big challenge. Herein, a composite material consisting of TC@WO3@g‐C3N4@Ni‐NiO complex matrix as a bifunctional electrocatalyst for the OER and HER is described. Though the catalyst has modest activity for HER, it exhibits high OER activity thereby making it a better nonprecious electrocatalyst for both OER and HER and is further improved by g‐C3N4. The catalytic activity arises from the synergetic effects between WO3, Ni‐NiO, and g‐C3N4. A Ni‐NiO alloy and WO3 nanoparticles decorated on the g‐C3N4 surface supported toray carbon (TC) matrix (TC@WO3@g‐C3N4@Ni‐NiO) by a facile route that show an excellent and durable bifunctional catalytic activity for OER and HER in the alkaline medium are developed. This carbon nitride with binary metal/metal‐oxide matrix supported with TC exhibit an overpotential of 0.385 and 0.535 V versus RHE at a current density of 10 mA cm−2 (Tafel slopes of 0.057 and 0.246 V dec−1 for OER and HER, respectively), in 0.1 m NaOH . The catalyst is tested in water electrolysis for 17 h.

In situ construction of hierarchical graphitic carbon nitride homojunction as robust bifunctional photoelectrocatalyst for overall water splitting

“…Such a low overpotential is comparable to the state‐of‐the‐art OER catalysts such as IrO 2 , RuO 2 and transition metal based catalysts . The OER parameters of typical catalysts in 1.0 mol L −1 KOH are listed in Table . This result indicates the possibility of designing highly active OER photo‐responsive electrocatalysts with earth‐abundant non‐metallic elements.…”

“…The rapid rising of current density for CN‐S(3:2) further confirms its superior OER performance, achieving a current density of 10 mA cm −2 at an overpotential of 500 mV. The OER performance of CN‐S(3:2) in alkaline solution is comparable to previously reported g‐C 3 N 4 ‐based materials …”

FeTiO3 Perovskite Nanoparticles for Efficient Electrochemical Water Splitting

“…The FeTiO3 perovskite nanoparticles coated on Toray carbon sheet, platinum (Pt) rod, and mercury/mercurous oxide (Hg/HgO) were used as working, counter, and reference electrodes, respectively. In all the measurements, the potential of Hg/HgO was converted into reversible hydrogen electrode (RHE) using the formula [23], E(RHE) = E 0 (Hg/HgO) + E(observed)+ 0.059pH V (1)…”

Strategies to improve electrocatalytic and photocatalytic performance of two-dimensional materials for hydrogen evolution reaction

“…However, its application to water splitting is limited by its poor conductivity. Graphene is a good conductive substrate material, and can be used as a support for g-C3N4 to promote water splitting [81,[244][245][246]. Jeong et al [81] modified C3N4 with graphene to modify its electron arrangement for water splitting applications.…”