Designing high-efficiency water oxidation catalysts from earth-abundant resources has attracted significant attention in the last couple of years owing to the potential application of this technology in several energy conversion devices. Among the transition metals, copper is one of the cheapest earth-abundant nonprecious element which can enhance electrocatalytic activity due to heavily occupied d-orbitals. In this article we have shown electrocatalytic activity of copper selenide for the first time for water oxidation reaction. The copper selenide phases were synthesized by direct electrodeposition on electrodes, as well as by hydrothermal and chemical vapor deposition (CVD) techniques. Structure and morphology characterization through powder X-ray diffraction, Raman, X-photoelectron spectroscopy, and electron microscopy revealed that all the synthesized phases were pure crystalline copper selenide of composition Cu 2 Se and comprising nanostructured granular morphology. Electrocatalytic performance for water oxidation was investigated in alkaline solution (1 M KOH) and it was observed that Cu 2 Se showed a low overpotential of only 270 mV to achieve 10 mA cm −2 . This catalyst also displayed a low Tafel slope of 48.1 mV dec −1 . Interestingly Cu 2 Se showed comparable electrocatalytic activity irrespective of the method of synthesis indicating that it is indeed an intrinsic property of the material. Chronoamperometric studies revealed that the catalyst retained its activity for prolonged periods of continuous oxygen evolution exceeded 6 h, while postactivity characterization revealed that crystallinity and surface composition was preserved after catalytic activity. Because copper selenides can be found in nature as stable minerals, this article can initiate a new concept for efficient catalyst design.

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In this article solvothermally synthesized copper selenide nanostructures have been resported as highly efficient electrocatalysts for carbon dioxide reduction under ambient conditions with high selectivity for carbon-rich C2 products at...

The organocatalytic behavior of N-heterocyclic carbenes in the aerobic oxidation of aromatic aldehydes to esters with boronic acids has been explored. This transition metal-free protocol allows access to a wide variety of aromatic esters in good to excellent yields under mild reaction conditions.

Copper cobalt selenide, CuCo2Se4, has been identified as an efficient catalyst for electrocatalytic CO2 reduction, exhibiting high selectivity for carbon-rich and value-added products. Achieving product selectivity is one of the primary challenges for CO2 reduction reactions, and the catalyst surface plays a pivotal role in determining the reaction pathway and, more importantly, the intermediate adsorption kinetics leading to C1- or C2+-based products. In this research, the catalyst surface was designed to optimize the adsorption of the intermediate CO (carbonyl) group on the catalytic site such that its dwell time on the surface was long enough for further reduction to carbon-rich products but not strong enough for surface passivation and poisoning. CuCo2Se4 was synthesized through hydrothermal method, and the assembled electrode showed the electrocatalytic reduction of CO2 at various applied potentials ranging from −0.1 to −0.9 V vs RHE. More importantly, it was observed that the CuCo2Se4-modified electrode could produce exclusive C2 products such as acetic acid and ethanol with 100% faradaic efficiency at a lower applied potential (−0.1 to −0.3 V), while C1 products such as formic acid and methanol were obtained at higher applied potentials (−0.9 V). Such high selectivity and preference for acetic acid and ethanol formation highlight the novelty of this catalyst. The catalyst surface was also probed through density functional theory (DFT) calculations, and the high selectivity for C2 product formation could be attributed to the optimal CO adsorption energy on the catalytic site. It was further estimated that the Cu site showed a better catalytic activity than Co; however, the presence of neighboring Co atoms with the residual magnetic moment on the surface and subsurface layers influenced the charge density redistribution on the catalytic site after intermediate CO adsorption. In addition to CO2 reduction, this catalytic site was also active for alcohol oxidation producing formic or acetic acid from methanol or ethanol, respectively, in the anodic chamber. This report not only illustrates the highly efficient catalytic activity of CuCo2Se4 for CO2 reduction with high product selectivity but also offers a proper insight of the catalyst surface design and how to obtain such high selectivity, thereby providing knowledge that can be transformative for the field.