State-of-the-Art Advances and Perspectives for Electrocatalysis

Poly(3-aminobenzoic acid) Decorated with Cobalt Zeolitic Benzimidazolate Framework for Electrochemical Production of Clean Hydrogen

“…Firstly, the adsorption of the hydrogen proton on the surface of an electrocatalyst results in a Volmer reaction [ 16 ]: where T and R stand for the thermodynamic temperature (K) and gas constant (8.31451 J mol −1 K −1 ), respectively. 0.5 is the symmetry coefficient, and F is Faraday’s number (96,485 C mol −1 ) [ 1 ]. This is followed by either a reaction between an adsorbed hydrogen and a proton from the electrolyte (electrochemical desorption or Heyrovsky reaction) [ 4 ] or a reaction between two adsorbed hydrogen protons next to each other to give molecular hydrogen [ 21 , 33 ]: …”

“…Hydrogen gas (H 2 ) is regarded as an alternative energy carrier for decreasing our dependency on fossil fuels (coal and oil) as well as reducing the greenhouse and other harmful gas emissions resulting from the energy processing of those fossil-fuel-based resources [ 1 , 2 , 3 , 4 ]. H 2 gas can be produced by various methods, which include coal gasification, the steam reforming of natural gases and water splitting via photocatalysis or electrolysis [ 1 , 3 ]. Among these methods, electrochemical water splitting (EWS) (2H 2 O = 2H 2 + O 2 ) is the most promising and effective approach for achieving the abovementioned developments (coal gasification and steam reforming still produce greenhouse gases) [ 4 ].…”

“…Among these methods, electrochemical water splitting (EWS) (2H 2 O = 2H 2 + O 2 ) is the most promising and effective approach for achieving the abovementioned developments (coal gasification and steam reforming still produce greenhouse gases) [ 4 ]. During EWS, there are two important half-cell reactions taking place, viz., the hydrogen evolution reaction (HER) (4H + + 4 e − = 2H 2 ) and oxygen evolution reaction (OER) (2H 2 O = O 2 + 4H + + 4e − ) on the cathodic and anodic electrodes, respectively [ 1 , 2 , 5 , 6 ]. Both half-cell reactions require an electrode material that is highly electrocatalytically efficient, chemically and thermally stable and cost effective [ 6 , 7 ].…”

“…Both half-cell reactions require an electrode material that is highly electrocatalytically efficient, chemically and thermally stable and cost effective [ 6 , 7 ]. Currently, noble/precious transition metals including platinum (Pt), ruthenium (Ru) and palladium (Pd) are ideal HER electrocatalysts [ 1 ]. For example, Luo et al [ 2 ] fabricated the Pt-based electrodes supported on Ru-Vulcan carbon (VC) for HER applications.…”

“…The Pt-SAs/C electrocatalyst possessed high electrocatalytic HER activity with an overpotential of 36 mV to achieve a current density of 10 mA/cm 2 , a Tafel slope of 43 mV/dec and an outstanding stability up to 5000 cycles [ 7 ]. These metals are electrocatalytically active and stable, and have large cathodic current densities at lower overpotentials; however, high capital costs and scarcity greatly restrict their large-scale applications [ 1 , 6 , 8 ]. The quest for finding noble-metal-free and inexpensive HER electrocatalysts that exhibit similar activity with precious group metals is required.…”