Design Principles for Tungsten Oxide Electrocatalysts for Water Splitting

Abstract

Electrocatalytic water splitting involving the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is a crucial and effective pathway to obtain clean and renewable energy resources. The advanced electrocatalysts can significantly reduce the reaction energy barrier to realize high‐efficiency energy conversion. In this regard, noble‐metal catalysts display excellent catalytic performance for the water splitting reaction, but the high cost hinders its large‐scale application. As a low‐cost candidate for noble‐metal catalysts, tungsten oxide is endowed with the variable crystalline phase and adjustable composition, which provide more opportunities to achieve satisfactory catalytic activity by engineering crystal structure and modulating surface electronic states. To promote the reaction activity and stability, some effective strategies have been developed to optimize the surface crystal and electronic structure of tungsten oxide electrocatalysts for overall water splitting. In this review, we especially highlight the latest advances and progress in the exploration of tungsten oxide electrocatalysts for HER and OER, and systematically classify these strategies into several design principles involving adjustable surface morphology, engineering defects, and synergistic catalysis, providing a deep understanding of the relationship between the catalytic activity and crystal structure in the tungsten oxide. Some perspectives are also proposed to guide a rational design of tungsten oxide electrocatalyst for water splitting.

Block Copolymer Templated WO3 Surface Nanolines as Catalysts for Enhanced Epinephrine Sensing and the Oxygen Evolution Reaction

“…A decrease of surface resistance was also observed by EIS, with a smaller semicircle recorded under light illumination. The OER reaction mechanism can be attributed to the oxidation of water by using holes on the valance band of WO 3 with or without light irradiation [57] . Previous studies have also reported that oxygen vacancies on the surface of WO 3 decreased overpotential for OER and increased catalytic activity [58] .…”

“…The OER reaction mechanism can be attributed to the oxidation of water by using holes on the valance band of WO 3 with or without light irradiation. [57] Previous studies have also reported that oxygen vacancies on the surface of WO 3 decreased overpotential for OER and increased catalytic activity. [58] Overall, these results demonstrate that the WO 3 NLs-ITO electrodes exhibit catalytic activity both in the absence and presence of light illumination, with increased catalytic activity under illumination.…”

Anodizing Tungsten Foil with Ionic Liquids for Enhanced Photoelectrochemical Applications

“…In the same way, during photoelectrochemical water splitting, electron–hole pairs are photogenerated in the conduction and valence layers, respectively. Then, they separate, and holes oxidize the water molecules to create O 2 and H + on the surface of the semiconductor, and electrons in the counter electrode reduce H + into gaseous hydrogen [ 23 , 24 , 25 ].…”

Ultrathin Al2O3 Protective Layer to Stabilize the Electrochromic Switching Performance of Amorphous WOx Thin Films

“…[1,2] Due to their diversity and versatility, transition metal oxides play a central role in energy-related applications, [3][4][5][6][7] such as lithium-ion batteries, supercapacitors, photo-and electrocatalysts or electrochromic (EC) devices. [8][9][10][11][12][13][14][15][16][17] In order to stabilize the oxides against undesired side reactions, thin inert protective layers can be used as shown, e.g., for cathode materials in lithium-ion batteries. [18][19][20][21] EC devices have the potential to play a key role in energy saving in the building sector, which accounts for 42 % of the European energy consumption.…”