Surface-assembled non-noble metal nanoscale Ni-colloidal thin-films as efficient electrocatalysts for water oxidation

• Published in: RSC advances 2019-11, Vol.9 (64), p.37274-37286
• Main Authors: Babar, Noor-Ul-Ain, Saddiqa, Ayesha, Nisar, Laraib, Gilani, Syeda Robina, Joya, Khurram Saleem
• Format: Article
• Language: English
• Subjects: Annealing; Chemical energy; Chemistry; Colloids; Electrocatalysts; Electrolysis; Energy conversion; Hydrogen production; Nanoparticles; Nickel; Noble metals; Organic chemistry; Oxidation; Porosity; Reaction kinetics; Stability analysis; Tafel slopes; Thin films; Ultrafines
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c9ra07388d

A highly operative and inexpensive water oxidation scheme using an efficient nanoscale electrocatalyst is vastly demanded for optimum H 2 production, CO 2 reduction, and has attracted increased attention for chemical energy conversion. We present here a simple route to make efficient electrocatalytic colloidal nanoparticles of nickel out of mere metal ions in a simple borate buffer system. The simple and annealed Ni-colloidal nanoparticles (Ni-CNPs) resulted in a facile transformation into ultrafine films, which further activated the catalysts, while initiating OER just at the overpotential η = 250 mV (1.48 V vs. RHE) under benign conditions. They also showed high porosity and favorable kinetics while displaying impressive Tafel slopes of just 51 mV dec −1 , and a high TOF value of 0.79 s −1 at 0.35 V was observed for Ni-CNPs/FTO 500 . These electrocatalysts also showed long-term stability during the bulk water electrolysis experiment conducted for a continuous 20 hours without notable catalytic degradation, which ensures their economic benefits. The electrochemical data, CVs, kinetic study, short-term durability, extended catalytic stability, SEM analysis, and other supporting data provide compelling evidence that these non-precious, metal-based, electroactive, catalytic, colloidal thin-films (simple and annealed) with nanoscale morphological attributes presented promising catalytic performance under the conditions used herein. Highly applied and accessible electrocatalytic system derived from simple Ni-colloids has been explored to facilely derive kinetically sluggish water oxidation reaction. Ni-catalysts also present well-balanced kinetics of OER and high durability.