Platinum atomic clusters embedded in polyoxometalates-carbon black as an efficient and durable catalyst for hydrogen evolution reaction

Polyoxometalate-derived electrocatalysts enabling progress in hydrogen evolution reactions

Platinum-based catalysts exhibit outstanding electrocatalytic performance in the hydrogen evolution reaction (HER). However, platinum-based catalysts face significant challenges due to their rarity and high cost. This paper endeavors to shed light on a promising alternative: polyoxometalate (POM)-based catalysts, which possess significant potential for the synthesis of non-noble metal-based catalysts for the HER. Utilizing POMs as raw materials to assemble POM-derived materials, including POM-derived crystalline materials, metal sulfides, phosphides, carbides, nitrides, and so on, has emerged as an effective approach for the synthesis of hydrogen evolution electrocatalysts. This approach offers advantages in both stability and electrocatalytic performance. This comprehensive review navigates through latest progress in the assembly strategy and HER performance of POM-based crystal materials, alongside discussion on transition metal compounds derived from POMs, such as carbides, phosphides, and sulfides. Besides, future developments in POM-derived electrocatalyst regulation of the electrochemical HER are prospected.

Electron-Sponge Nature of Polyoxometalates for Next-Generation Electrocatalytic Water Splitting and Nonvolatile Neuromorphic Devices

Designing next-generation molecular devices typically necessitates plentiful oxygen-bearing sites to facilitate multiple-electron transfers. However, the theoretical limits of existing materials for energy conversion and information storage devices make it inevitable to hunt for new competitors. Polyoxometalates (POMs), a unique class of metal-oxide clusters, have been investigated exponentially due to their structural diversity and tunable redox properties. POMs behave as electron-sponges owing to their intrinsic ability of reversible uptake-release of multiple electrons. In this review, numerous POM-frameworks together with desired features of a contender material and inherited properties of POMs are systematically discussed to demonstrate how and why the electron-sponge-like nature of POMs is beneficial to design next-generation water oxidation/reduction electrocatalysts, and neuromorphic nonvolatile resistance-switching random-access memory devices. The aim is to converge the attention of scientists who are working separately on electrocatalysts and memory devices, on a point that, although the application types are different, they all hunt for a material that could exhibit electron-sponge-like feature to realize boosted performances and thus, encouraging the scientists of two completely different fields to explore POMs as imperious contenders to design next-generation nanodevices. Finally, challenges and promising prospects in this research field are also highlighted.

Layer-by-Layer Construction of a Nanoarchitecture by Polyoxometalates and Polymers: Enhanced Electrochemical Hydrogen Evolution Reaction

In this contribution, a nanoarchitectural approach was employed to produce a nanolayer of polyoxometalate (POM) on the surface of a glassy carbon electrode (GCE) to achieve a higher surface area with higher electrocatalytic activity toward the electrochemical hydrogen evolution reaction (HER). To accomplish this, the well-known layer-by-layer (LbL) technique was employed, which involved the alternate adsorption of the POM, Na_0.3[N(C₄H₉)₄]_7.7 [(Mo₃O₈)₄(O₃PC(O)(C₃H₆NH₂CH₂C₄H₃S)PO₃)₄], abbreviated as [(TBA)Mo₁₂(AleThio)₄], and polyethyleneimine (PEI) polymer. This nanolayered electrode exhibited catalytic properties toward the HER in 0.5 M H₂SO₄ with the resulting polarization curves indicating an increase in the HER activity with the increasing number of POM layers, and the overpotential required for this reaction was lowered by 0.83 V when compared with a bare GCE. The eighth PEI/[(TBA)Mo₁₂(AleThio)₄] bilayer exhibited a significantly lower HER overpotential of -0.077 V at a current density of 10 mA cm^-2. Surface characterization of the LbL-assembled nanolayers was carried out using X-ray photoelectron spectroscopy, atomic force microscopy, and scanning electron microscopy. We believe that the synergetic effect of the positively charged PEI polymer and the catalytically active molybdate POM is the cause for the successful response to the electrochemical HER.

Heterogeneous catalysis mediated by light, electricity and enzyme via machine learning: Paradigms, applications and prospects

Energy crisis and environmental pollution have become the bottleneck of human sustainable development. Therefore, there is an urgent need to develop new catalysts for energy production and environmental remediation. Due to the high cost caused by blind screening and limited valuable computing resources, the traditional experimental methods and theoretical calculations are difficult to meet with the requirements. In the past decades, computer science has made great progress, especially in the field of machine learning (ML). As a new research paradigm, ML greatly accelerates the theoretical calculation methods represented by first principal calculation and molecular dynamics, and establish the physical picture of heterogeneous catalytic processes for energy and environment. This review firstly summarized the general research paradigms of ML in the discovery of catalysts. Then, the latest progresses of ML in light-, electricity- and enzyme-mediated heterogeneous catalysis were reviewed from the perspective of catalytic performance, operating conditions and reaction mechanism. The general guidelines of ML for heterogeneous catalysis were proposed. Finally, the existing problems and future development trend of ML in heterogeneous catalysis mediated by light, electricity and enzyme were summarized. We highly expect that this review will facilitate the interaction between ML and heterogeneous catalysis, and illuminate the development prospect of heterogeneous catalysis.