Electrocatalysts for Hydrogen Evolution in Alkaline Electrolytes: Mechanisms, Challenges, and Prospective Solutions

Abstract

Hydrogen evolution reaction (HER) in alkaline medium is currently a point of focus for sustainable development of hydrogen as an alternative clean fuel for various energy systems, but suffers from sluggish reaction kinetics due to additional water dissociation step. So, the state‐of‐the‐art catalysts performing well in acidic media lose considerable catalytic performance in alkaline media. This review summarizes the recent developments to overcome the kinetics issues of alkaline HER, synthesis of materials with modified morphologies, and electronic structures to tune the active sites and their applications as efficient catalysts for HER. It first explains the fundamentals and electrochemistry of HER and then outlines the requirements for an efficient and stable catalyst in alkaline medium. The challenges with alkaline HER and limitation with the electrocatalysts along with prospective solutions are then highlighted. It further describes the synthesis methods of advanced nanostructures based on carbon, noble, and inexpensive metals and their heterogeneous structures. These heterogeneous structures provide some ideal systems for analyzing the role of structure and synergy on alkaline HER catalysis. At the end, it provides the concluding remarks and future perspectives that can be helpful for tuning the catalysts active‐sites with improved electrochemical efficiencies in future.

Hollow Porous Heterometallic Phosphide Nanocubes for Enhanced Electrochemical Water Splitting

“…In recent years, nonprecious metal‐based nanomaterials have been recognized as alternative electrocatalysts for HER and OER . Among them, transition metal chalcogenides, carbides, and phosphides have shown potential as highly active and stable catalysts for HER . On the other hand, transition metal oxides and hydroxides have been investigated for catalyzing OER in alkaline electrolytes .…”

Ni(OH)2‐WP Hybrid Nanorod Arrays for Highly Efficient and Durable Hydrogen Evolution Reactions in Alkaline Media

“…[26] Wu et al also confirmed that WP/W nanorod array electrodes exhibit as ignificantly enhanced HER efficiency. [28,29] HER usually proceeds in two steps:t he initial formation of hydrogen intermediates (H ads ,V olmer step) ands ubsequentg eneration of H 2 (Heyrovsky and Ta fel step). Generally,t hey suffer from ah igh overpotential in alkaline solutionso wing to the high energy barrier resulting from the sluggish HER kineticsi na lkaline media.…”

Integrating Catalysis of Methane Decomposition and Electrocatalytic Hydrogen Evolution with Ni/CeO2 for Improved Hydrogen Production Efficiency

“…[9] However, the high cost and scarcity of constituentp latinum hinders their suitability for practical applications. [11] Metallic nickel is effective in expediting the HER, [12] but improving the relatively low catalytic activity and conductivity through optimizing nickelbased catalysts remains challenging. [11] Metallic nickel is effective in expediting the HER, [12] but improving the relatively low catalytic activity and conductivity through optimizing nickelbased catalysts remains challenging.…”