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Perovskite oxides have emerged as promising candidates for the oxygen evolution reaction (OER) electrocatalyst due to their flexible lattice structure, tunable electronic structure, superior stability, and cost-effectiveness. Recent research studies have mostly focused on the traditional methods to tune the OER performance, such as cation/anion doping, A-/B-site ordering, epitaxial strain, oxygen vacancy, and so forth, leading to reasonable yet still limited activity enhancement. Here, we report a novel strategy for promoting the OER activity for perovskite LaNiO3 by crystal phase engineering, which is realized by breaking long-range chemical bonding through amorphization. We provide the first and direct evidence that perovskite oxides with an amorphous structure can induce the self-adaptive process, which helps enhance the OER performance. This is evidenced by the fact that an amorphous LaNiO3 film on glassy carbon shows a 9-fold increase in the current density compared to that of an epitaxial LaNiO3 single crystalline film. The obtained current density of 1038 μΑ cm-2 (@ 1.6 vs RHE) is the largest value among the literature reported values. Our work thus offers a new protocol to boost the OER performance for perovskite oxides for future clean energy applications.

Layered two-dimensional (2D) materials have received tremendous attention due to their unique physical and chemical properties when downsized to single or few layers. Several types of layered materials, especially transition metal dichalcogenides (TMDs) have been demonstrated to be good electrode materials due to their interesting physical and chemical properties. Apart from TMDs, post-transition metal chalcogenides (PTMCs) recently have emerged as a family of important semiconducting materials for electrochemical studies. PTMCs are layered materials which are composed of post-transition metals raging from main group IIIA to group VA (Ga, In, Ge, Sn, Sb and Bi) and group VI chalcogen atoms (S, selenium (Se) and tellurium (Te)). Although a large number of literatures have reviewed the electrochemical and electrocatalytic applications of TMDs, less attention has been focused on PTMCs. In this review, we focus our attention on PTMCs with the aim to provide a summary to describe their fundamental electrochemical properties and electrocatalytic activity towards hydrogen evolution reaction (HER). The characteristic chemical compositions and crystal structures of PTMCs are firstly discussed, which are different from TMDs. Then, inherent electrochemistry of PTMCs is discussed to unveil the well-defined redox behaviors of PTMCs, which could potentially affect their efficiency when applied as electrode materials. Following, we focus our attention on electrocatalytic activity of PTMCs towards HER including novel synthetic strategies developed for the optimization of their HER activity. This review ends with the perspectives for the future research direction in the field of PTMC based electrocatalysts.

Self-activating MMoO4 (M = Mg, Ca, Sr) phosphors was successfully synthesized via a polyacrylamide gel method with citric acid used as a chelating agent. The phase evolution process, crystal structure, surface morphology, color and photoluminescent properties of MgMoO4, CaMoO4 and SrMoO4 phosphors have been systematically studied. X-ray powder diffraction and fourier transform infrared spectroscopy revealed that the phase formation temperature of MMoO4 decreases with the increase of M ion radius. Scanning electron microscopy illustrated the flake (MgMoO4), spherical (CaMoO4) and spherical (SrMoO4) like morphologies. Photoluminescence spectra indicated the broad emission peak maximum at 524 (MgMoO4), 435 (CaMoO4), and 378 nm (SrMoO4) under 375, 284 and 217 nm excitation.