Metal Electrocatalysts for Hydrogen Production in Water Splitting

Abstract

The rising demand for fossil fuels and the resulting pollution have raised environmental concerns about energy production. Undoubtedly, hydrogen is the best candidate for producing clean and sustainable energy now and in the future. Water splitting is a promising and efficient process for hydrogen production, where catalysts play a key role in the hydrogen evolution reaction (HER). HER electrocatalysis can be well performed by Pt with a low overpotential close to zero and a Tafel slope of about 30 mV dec −1 . However, the main challenge in expanding the hydrogen production process is using efficient and inexpensive catalysts. Due to electrocatalytic activity and electrochemical stability, transition metal compounds are the best options for HER electrocatalysts. This study will focus on analyzing the current situation and recent advances in the design and development of nanostructured electrocatalysts for noble and non-noble metals in HER electrocatalysis. In general, strategies including doping, crystallization control, structural engineering, carbon nanomaterials, and increasing active sites by changing morphology are helpful to improve HER performance. Finally, the challenges and future perspectives in designing functional and stable electrocatalysts for HER in efficient hydrogen production from water-splitting electrolysis will be described.

Covalent Molecular Anchoring of Metal-Free Porphyrin on Graphitic Surfaces toward Improved Electrocatalytic Activities in Acidic Medium

“…To deal with this challenge, numerous scientific studies focusing on non-precious metals as well as metal-free-based catalysts for enhancing the HER and OER processes have been conducted. For instance, metal and/or metal-oxide-based catalysts have received much attention due totheirlowcost, morphology and facets, as well as defect-tuned optoelectronic properties, which are favorable for overall water splitting [14][15][16][17][18][19]. Nonetheless, their inherent disadvantages such as low charge mobility and self-degradation have thus far resulted in low conversion efficiency and stability [20][21][22].…”