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Developing efficient catalysts for electrochemical CO2 reduction reaction (ECO2RR) to hydrocarbons is becoming increasingly important but still challenging due to their high overpotential and poor selectivity. Here, the famous Heusler alloys are investigated as ECO2RR catalysts for the first time by means of density functional theory calculations. The linear scaling relationship between the adsorption energies of CHO (and COOH) and CO intermediates is broken and, thus, the overpotential can be tuned regularly by chemically permuting different 3d, 4d, or 5d transition metals (TMs) in Heusler alloy Cu2TMAl. Cu2ZnAl shows the best activity among all the 30 Heusler alloys considered in the present study, with 41% improvement in energy efficiency compared to pure Cu electrode. Cu2PdAl, Cu2AgAl, Cu2PtAl, and Cu2AuAl are also good candidates. The calculations on the competition between hydrogen evolution reaction and CO2RR indicate that Cu2ZnAl is also the one having the best selectivity toward hydrocarbons. This work identifies the possibility of applying the Heusler alloy as an efficient ECO2RR catalyst. Since thousands of Heusler alloys have been found in experiments, the present study also encourages the search for more promising candidates in this broad research area. [ABSTRACT FROM AUTHOR]

The electrocatalytic conversion of CO2 into value‐added chemicals is a promising approach to realize a carbon‐energy balance. However, low current density still limits the application of the CO2 electroreduction reaction (CO2RR). Metal–organic frameworks (MOFs) are one class of promising alternatives for the CO2RR due to their periodically arranged isolated metal active sites. However, the poor conductivity of traditional MOFs usually results in a low current density in CO2RR. We have prepared conductive two‐dimensional (2D) phthalocyanine‐based MOF (NiPc‐NiO4) nanosheets linked by nickel‐catecholate, which can be employed as highly efficient electrocatalysts for the CO2RR to CO. The obtained NiPc‐NiO4 has a good conductivity and exhibited a very high selectivity of 98.4 % toward CO production and a large CO partial current density of 34.5 mA cm−2, outperforming the reported MOF catalysts. This work highlights the potential of conductive crystalline frameworks in electrocatalysis. [ABSTRACT FROM AUTHOR]

The electrocatalytic conversion of CO2 into value‐added chemicals is a promising approach to realize a carbon‐energy balance. However, low current density still limits the application of the CO2 electroreduction reaction (CO2RR). Metal–organic frameworks (MOFs) are one class of promising alternatives for the CO2RR due to their periodically arranged isolated metal active sites. However, the poor conductivity of traditional MOFs usually results in a low current density in CO2RR. We have prepared conductive two‐dimensional (2D) phthalocyanine‐based MOF (NiPc‐NiO4) nanosheets linked by nickel‐catecholate, which can be employed as highly efficient electrocatalysts for the CO2RR to CO. The obtained NiPc‐NiO4 has a good conductivity and exhibited a very high selectivity of 98.4 % toward CO production and a large CO partial current density of 34.5 mA cm−2, outperforming the reported MOF catalysts. This work highlights the potential of conductive crystalline frameworks in electrocatalysis. [ABSTRACT FROM AUTHOR]

It is highly desirable to develop efficient and low‐cost electrocatalysts for the oxygen evolution reaction (OER) to improve the efficiency of water electrolysis. Here, we report a strategy doping with a small amount of phosphorus to make inactive and low‐cost spinel CuCo2O4 (CCO) turn into high‐efficiency and superior to the noble metal catalyst RuO2. The spinel CuCo2O4−P0.5 (CCP0.5) shows the best OER performance with a small overpotential of 290 mV at a current density of 10 mA cm−2 and a low Tafel slope of 68 mV dec−1 in an alkaline electrolyte. The phosphorus doping induces the production of an amorphous phase that provides a large number of active sites, and the synergistic effect of the crystalline phase and amorphous phase significantly improves the OER activity of CCO. It is also revealed that the conductivity of CCO is improved compared with pristine CCO. Our work highlights that non‐metallic element doping is an effective strategy to greatly enhance the OER performance of spinel transition metal oxide electrocatalysts. [ABSTRACT FROM AUTHOR]

It is still a great challenge to achieve high selectivity of CH4 in CO2 electroreduction reactions (CO2RR) because of the similar reduction potentials of possible products and the sluggish kinetics for CO2 activation. Stabilizing key reaction intermediates by single type of active sites supported on porous conductive material is crucial to achieve high selectivity for single product such as CH4. Here, Cu2O(111) quantum dots with an average size of 3.5 nm are in situ synthesized on a porous conductive copper‐based metal–organic framework (CuHHTP), exhibiting high selectivity of 73 % towards CH4 with partial current density of 10.8 mA cm−2 at −1.4 V vs. RHE (reversible hydrogen electrode) in CO2RR. Operando infrared spectroscopy and DFT calculations reveal that the key intermediates (such as *CH2O and *OCH3) involved in the pathway of CH4 formation are stabilized by the single active Cu2O(111) and hydrogen bonding, thus generating CH4 instead of CO. [ABSTRACT FROM AUTHOR]

Electrochemical oxygen reduction offers an efficient and environmentally friendly route for hydrogen peroxide (H2O2) generation. This electrochemical process can produce H2O2 on-site under ambient conditions. High selectivity and activity two-electron oxygen reduction reaction (2e− ORR) catalysts are crucial for efficient electrochemical H2O2 synthesis. Here, metal/metal oxide, carbon material, and single-atom based 2e− ORR catalysts developed to produce H2O2 are reviewed. As the performance of the catalysts strongly depends on the pH values of electrolytes, pH effects and reaction mechanisms for the catalysts are further summarized to give a deep insight into this research area. This review would help us better understand the catalysts for electrochemical H2O2 synthesis and their rational design in the future. [ABSTRACT FROM AUTHOR]

An excellent nonlinear optical (NLO) material should satisfy many critical requirements simultaneously. How to balance all the requirements is a challenge, as they cause contradictory demands on structural attributes. Here, we use a high entropy strategy to integrate the advantages of ZnSe for a large NLO coefficient and a planar [InSe3]3− functional motif for phase matching. The resulting Ba6In6Zn4Se19 crystal shows excellent comprehensive NLO properties, i.e. a large effective NLO coefficient (2 × AgGaS2), a high laser induced damage threshold (LIDT, 15.5 × AgGaS2), a wide transmission range (0.52–22.5 μm), and an increased birefringence (Δn = 0.098) for phase matching. Theoretical calculations indicate that planar [InSe3]3− is an effective NLO functional motif for tuning birefringence and the "cocktail effect" realized via the high entropy strategy is important to improve the overall NLO performance. This study provides a promising way of developing new NLO materials with excellent comprehensive performance. [ABSTRACT FROM AUTHOR]