Electrocatalytic acidic oxygen evolution reaction: From nanocrystals to single atoms

Abstract

Hydrogen is the most preferred choice as an energy source to replace the nonrenewable energy resources such as fossil fuels due to its beneficial features of abundance, ecofriendly, and outstanding gravimetric energy density. Splitting water through a proton exchange membrane (PEM) electrolyzer is a well‐known method of hydrogen production. But the major impediment is the sluggish kinetics of oxygen evolution reaction (OER). Currently, scientists are struggling to build out an acid‐stable electrocatalyst for OER with low overpotential and excellent stability. In this review, the reaction mechanism and characterization parameters of OER are introduced, and then the improvement method of metal nanocatalysts (noble metal catalysts and noble metal‐free catalysts) in acidic media is discussed. Particularly, the application of single‐atom catalysts in acidic OER is summarized, which is current researching focus. At the same time, we also briefly introduced the cluster phenomenon, which is easy to occur in the preparation of single‐atom catalysts. More importantly, we summarized the in situ characterization methods such as in situ X‐ray absorption spectroscopy, in situ X‐ray photoelectron spectroscopy, and so forth, which are conducive to further understanding of OER reaction intermediates and active sites. Finally, we put forward some opinions on the development of acidic OER.

Copper-Based Metal–Organic Framework with a Tetraphenylethylene-Tetrazole Linker for Visible-Light-Driven CO2 Photoconversion

“…Nowadays, humans are facing a global energy shortage and climate problems, of which carbon dioxide is a major contributor to the greenhouse effect; meanwhile, CO 2 is an important carbon source. − The development of powerful technologies for converting CO 2 into chemicals and fuels can address both climate warming and energy shortages. − CO 2 photoreduction, which mimics the photosynthesis process in nature, has received tremendous attention. , Solar energy sources as renewable energy can be potential candidates for fulfilling future energy demands and sustainable technology. , By introducing suitable photocatalysts under solar energy, CO 2 photoreduction to value-added C1/C2 fuel (such as CO, CH 3 OH, CH 4 , and C 2 H 5 OH) is the ultimate goal of the green chemistry technology. , In the CO 2 photoreduction process, a photocatalyst with excellent performance occupies a central position. , The emergence of the TiO 2 photocatalyst promotes the development of solar fuel fields . Since then, various photocatalysts such as noble metals and their oxides have been widely used in photocatalyst reaction systems. − Although great progress has been made in this field, developing efficient and inexpensive photocatalysts remains a challenge.…”

Acid Anion Electrolyte Effects on Platinum for Oxygen and Hydrogen Electrocatalysis

“…Charge passed values of 74.1 ± 0.3 μC cm -2 , 83.1 ± 0.5 μC cm -2 , and 83.0 ± 0.3 μC cm -2 were calculated for perchloric, nitric, and sulfuric acids, respectively. Less charge passed in perchloric acid may indicate less anion adsorption versus oxide coverage, which could in turn allow for better OER activity owing to more available active sites 89,90 . Similarly, nitric and sulfuric acids demonstrate quantitatively similar amounts of charge passed and accordingly have nearly identical OER activity profiles and onset potentials.…”

Electronic structure modulation of MnO2 by Ru and F incorporation for efficient proton exchange membrane water electrolysis

“…8 To address this issue, significant efforts have been devoted to increase cost-effectiveness by minimizing noble metal usage as well as improving the catalytic performance. 9–18…”

“…8 To address this issue, signicant efforts have been devoted to increase cost-effectiveness by minimizing noble metal usage as well as improving the catalytic performance. [9][10][11][12][13][14][15][16][17][18] Numerous techniques have been introduced to fabricate catalysts with low quantities of precious metals by mixing them with transition metals, such as alloying, core-shell nanoparticles, and single-atom catalysts. 5,[13][14][15]19,20 However, taking into account that some methods still require a substantial amount of precious metal precursors during catalyst fabrication, overall cost reduction is insignicant.…”

“…[9][10][11][12][13][14][15][16][17][18] Numerous techniques have been introduced to fabricate catalysts with low quantities of precious metals by mixing them with transition metals, such as alloying, core-shell nanoparticles, and single-atom catalysts. 5,[13][14][15]19,20 However, taking into account that some methods still require a substantial amount of precious metal precursors during catalyst fabrication, overall cost reduction is insignicant. To resolve this issue, transition metal derivatives themselves, such as metal oxides, nitrides, suldes, and phosphides, have been applied as OER catalysts in acidic media.…”