Mantsopa K Zamisa, Giuseppe Cavallaro, Busisiwe P Mabuea, Olayemi J Fakayode, Mayetu Segale, Dieketseng Tsotetsi, Peter R Makgwane, Bakang Mothudi, Mokhotjwa Dhlamini, Tumelo Seadira
This study examines the use of natural bentonite clay (BC) modified with aluminum and iron as low-cost electrocatalysts for the hydrogen evolution reaction (HER) in an acidic medium. The successful modification process was accompanied by changes in the basal spacing, an increase in the BET surface area and pore volume, and promotion of mass transfer for enhanced hydrogen production. After mechanically blending with silver (Ag) nanoclusters, the more sustainable and higher surface-area exhibiting Fe-clay composite showed about 21% increase in hydrogen production and a 134% increase in turnover frequency (TOF) relative to the reversible hydrogen electrode (RHE). The Ag-Fe-Clay composite achieved a current density of 274 mA/cm2, similar to that of the commercial palladium black catalyst at -1.20 V (vs RHE). This work demonstrates the potential of Ag-laced Fe-modified bentonite clay as a nonexpensive sustainable alternative to the state-of-the-art highly expensive (HER) catalysts with an industrial output of about 1018 mA/cm2 at -2.22 V vs RHE applied potential. Further work is ongoing to evaluate the performance of the clay with other metallic catalytic agents.