A catholically pre-treated low cost screen-printed carbon electrode surface for metal compounds electrocatalyst like hydrogen evolution activity

Search for simple and economical electrocatalyst for the hydrogen gas evolution reaction (HER), which can resemble to the performance of Pt and other precious metals, is a challenging research interest. In this work, a systematic effect of pre-treatment potential of screen-printed carbon (SPCE) surface on the HER performance in 0.5 M H2SO4 was carried out. A new observation of a low potential HER (onset potential, Eonset = −0.02 V vs. RHE) at a cathodic potential, −0.5 V vs. Ag/AgCl on 1 hr pre-treated screen-printed carbon electrode (SPCE*, * = pre-treated) was observed. Physicochemical and electrochemical characterizations of the SPCE* by field emission scanning electron-microscope, Raman, IR and X-Ray photoelectron spectroscopes reveals specific generation of carboxylic acid functionalized carbon surface and in turn for the enhanced HER on the modified electrode surface. Electrochemical characterization of SPCE* with Fe(CN)63− support the observation. A marked decrement in the peak current and significant increase in the peak-to-peak separation potential response due electrostatic repulsion between the anion sites of Fe(CN)63− and –COO– were noticed. This observation is in parallel with the reduced electrical double layer capacitance value of the SPCE* system. The Eonset and Tafel value (54.7 mV dec−1) obtained here are comparable to those at Pt, MoS2, MoSe2 and superior over the N- and P-doped graphene/carbon electrocatalysts for HER. A prototype HER system was developed and demonstrated for H2 gas production at a rate of 0.0053 μM s−1 (Operating potential = −0.5 V vs Ag/AgCl), which is comparable to that of precious metal and metal compound electrocatalysts based HER performance.