Catalyst Design through Grafting of Diazonium Salts—A Critical Review on Catalyst Stability

Abstract

In the pursuit of designing a reusable catalyst with enhanced catalytic activity, recent studies indicate that electrochemical grafting of diazonium salts is an efficient method of forming heterogeneous catalysts. The aim of this review is to assess the industrial applicability of diazonium-based catalysts with particular emphasis on their mechanical, chemical, and thermal stability. To this end, different approaches to catalyst production via diazonium salt chemistry have been compared, including the immobilization of catalysts by a chemical reaction with a diazonium moiety, the direct use of diazonium salts and nanoparticles as catalysts, the use of diazonium layers to modulate wettability of a carrier, as well as the possibility of transforming the catalyst into the corresponding diazonium salt. After providing descriptions of the most suitable carriers, the most common deactivation routes of catalysts have been discussed. Although diazonium-based catalysts are expected to exhibit good stability owing to the covalent bond created between a catalyst and a post-diazonium layer, this review indicates the paucity of studies that experimentally verify this hypothesis. Therefore, use of diazonium salts appears a promising approach in catalysts formation if more research efforts can focus on assessing their stability and long-term catalytic performance.

Flexible Copper Films Modification via Spontaneous Reduction of Aryldiazonium Gold Salts: Unraveling Surface Properties and Energy Profile

“…Most devised methodologies for grafting organic layers or AuNPs on copper metal have employed electrochemical processes for decades. − The electrochemical reduction of aryldiazonium salts on a copper surface to form strongly bonded organic layers has been employed to inhibit corrosion and develop ice-phobic surfaces . Mooste et al reported the electrochemical grafting of anthraquinone diazonium salts on copper electrodes .…”

Electrografting of Phenyl Phosphate Layers onto Glassy Carbon for Tuning Catalytic Activity toward the Hydrogen Evolution Reaction

“…Previous research has predominantly focused on modulating catalyst properties and investigating the impact of catalyst size, shape, and chemical composition [ 18 , 19 ]. Recently, chemically modified catalysts with thin organic layers were proposed as a promising approach to modulating electrocatalytic activity [ 20 ]. However, this approach is at an early stage and more research efforts are needed.…”