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Leaching of pyrite-type catalysts induced by surface oxidation and galvanic corrosion is a sign of poor electrocatalytic durability and limits their potential for the electrocatalytic hydrogen evolution reaction (HER). Weakened O2 adsorption on pyrites can suppress both oxidation and corrosion, preventing the loss of electroactive components and maintaining their activity. Herein, we report our strategy theoretically and experimentally to establish an engineered CoS2 surface by Ce-doping which exhibits improved electrochemical stability against galvanic corrosion and enhanced chemical stability against ambient surface oxidation for an efficient and robust HER in alkali over 250 h. The Ce-doped CoS2 electrode delivered an activity–durability factor of ∼31 times higher than that of the CoS2 electrode, indicating the highly stabilized HER activity. Characterization tests on the spent Ce-doped CoS2 showed negligible corrosion current and leached Co ions in the electrolyte, further demonstrating that the Ce-doping protected CoS2 from oxidation- and corrosion-induced leaching. [ABSTRACT FROM AUTHOR]

Abstract: Introducing cerium (Ce) species into electrocatalysts has been recently developed as an effective approach to improve their oxygen evolution reaction (OER) performance. Importantly, the spatial distribution of Ce species in the hosts can determine the availability of Ce species either as additives or as co‐catalysts, which would dictate their different contributions to the enhanced electrocatalytic performance. Herein, the comprehensive investigations on two different catalyst configurations, namely CeO2‐embedded NiO (Ce‐NiO‐E) and CeO2‐surface‐loaded NiO (Ce‐NiO‐L), are performed to understand the effect of their specific spatial arrangements on OER characteristics. The Ce‐NiO‐E catalysts exhibit a smaller overpotential of 382 mV for 10 mA cm−2 and a lower Tafel slope of 118.7 mV dec−1, demonstrating the benefits of the embedded configuration for OER, as compared with those of Ce‐NiO‐L (426 mV and 131.6 mV dec−1) and pure NiO (467 mV and 140.7 mV dec−1), respectively. The improved OER property of Ce‐NiO‐E originates from embedding small‐sized CeO2 clusters into the host for the larger specific surface area, richer surface defects, higher oxygen adsorption capacity, and better optimized electronic structures of the surface active sites, as compared with Ce‐NiO‐L. Above findings provide a valuable guideline for and insight in designing catalysts with different spatial configurations for enhanced catalytic properties. [ABSTRACT FROM AUTHOR]

A rapid and facile gaseous anion-exchange reaction between CsPbBr3 perovskite nanocrystals and HCl vapor was carried out under the ambient conditions. The resultant CsPb(Br/Cl)3 nanocrystals preserved the morphological features and crystal structure of the original CsPbBr3 nanocrystals and exhibited a significant blue-shift in the ultraviolet-visible light absorption and photoluminescence spectra. Inspired by the visual observations in the fluorimetry upon gaseous anion-exchange reaction, the CsPbBr3 nanocrystals were developed as highly sensitive and selective spectrochemical probes for the detection of toxic and corrosive HCl vapor with a concentration as low as 5 ppm. [ABSTRACT FROM AUTHOR]

Searching the high-efficient, stable, and earth-abundant electrocatalysts to replace the precious noble metals holds the promise for practical utilizations of hydrogen and oxygen evolution reactions (HER and OER). Here, a series of highly active and robust Co-doped nickel phosphides (Ni2− xCo xP) catalysts and their hybrids with reduced graphene oxide (rGO) are developed as bifunctional catalysts for both HER and OER. The Co-doping in Ni2P and their hybridization with rGO effectively regulate the catalytic activity of the surface active sites, accelerate the charge transfer, and boost their superior catalytic activity. Density functional theory calculations show that the Co-doped catalysts deliver the moderate trapping of atomic hydrogen and facile desorption of the generated H2 due to the H-poisoned surface active sites of Ni2− xCo xP under the real catalytic process. Electrochemical measurements reveal the high HER efficiency and durability of the NiCoP/rGO hybrids in electrolytes with pH 0-14. Coupled with the remarkable and robust OER activity of the NiCoP/rGO hybrids, the practical utilization of the NiCoP/rGO|NiCoP/rGO for overall water splitting yields a catalytic current density of 10 mA cm−2 at 1.59 V over 75 h without an obvious degradation and Faradic efficiency of ≈100% in a two-electrode configuration and 1.0 m KOH. [ABSTRACT FROM AUTHOR]

Oxygen evolution reaction (OER) catalysts are of central importance for electrocatalytic/photocatalytic water oxidation and fuel generation. Here we report a new type of ultrathin porous Co3O4 nanoplate as a highly efficient OER catalyst. The porous Co3O4 nanoplates annealed at 250 °C can be readily synthesized in large quantities with a large surface area of 160.9 m2 g−1, a very small crystalline size of ∼3.0 nm, and a thin thickness of ∼10 nm. The large surface area provides more surface active sites for the OER. The structural features of the porous nanoplates significantly enrich the amount of surface abundant catalytic sites, provide more active edge and corner cobalt species with low coordination numbers, and subsequently enhance their OER activity. Meanwhile, the thin thickness facilitates efficient diffusion of chemicals and the escape of the generated O2 within the electrode. Taken all together, the porous Co3O4 nanoplates annealed at 250 °C deliver a high OER activity with an overpotential as low as 258 mV at 1 mA cm−2, a turnover frequency of 0.0042 s−1 (low bound), a Tafel slope of 71 mV dec−1 in 1.0 M KOH solution and an excellent electrochemical stability. [ABSTRACT FROM AUTHOR]

We report a novel approach to synthesize ultra-thin β-Ni(OH)2 nanoplates with a thickness of 1.5-3.0 nm and their composites with multi-walled carbon nanotubes (MWCNTs) by one-step hydrothermal in the absence of surfactants. Ultra-thin β-Ni(OH)2 nanoplates have a large surface area of 139.0 m2 g-1, associated with more exposed surface Ni species, and exhibit better catalytic activity for oxygen evolution reaction (OER) than that of thick β-Ni(OH)2 nanoplates previously reported. Compared to β-Ni(OH)2 nanoplates alone and MWCNTs + Ni(OH)2 nanoplate physical mixture, the composite exhibits much higher electrocatalytic OER activity in terms of low onset overpotential, small Tafel slope, large exchange current density and high OER catalytic current densities at specific applied potentials. The Tafel slope of 87 mV dec-1 for the composite in pH 13 KOH is much smaller than that of β-Ni(OH)2 nanoplates (165 mV dec-1) and their physical mixture (140 mV dec-1). The enhanced catalytic activity of the MWCNTs/Ni(OH)2 composite could be ascribed to the synergic interface of MWCNTs and ultra-thin β-Ni(OH)2 nanoplates for improved conductivity, efficient chemical transfer and high oxidation state of Ni species in the composite electrodes by introducing MWCNTs. No obvious degradation of the OER catalytic current density of the composite electrode over a period of six hours was observed. [ABSTRACT FROM AUTHOR]

The frustrated Lewis pair (FLP) site of (Ce, Ce)-O on the CeO 2 (110) surface undergoes reconstruction to form (La, Ce)-O upon La-doping. The FLP site of (La, Ce)-O with the tailored local Lewis acid-base property and increased spatial distance between the Lewis acid and base facilitates the tandem transformation of styrene and CO 2 through the weakened adsorption of CO 2 while maintaining activation.

The CO 2 reduction reaction (CO 2 RR) into chemical products is a promising and efficient way to combat the global warming issue and greenhouse effect. The viability of the CO 2 RR critically rests with finding highly active and selective catalysts that can accomplish the desired chemical transformation. Single-atom catalysts (SACs) are ideal in fulfilling this goal due to the well-defined active sites and support-tunable electronic structure, and exhibit enhanced activity and high selectivity for the CO 2 RR. In this review, we present the recent progress of quantum-theoretical studies on electro- and photo-chemical conversion of CO 2 with SACs and frameworks. Various calculated products of CO 2 RR with SACs have been discussed, including CO, acids, alcohols, hydrocarbons and other organics. Meanwhile, the critical challenges and the pathway towards improving the efficiency of the CO 2 RR have also been discussed., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (This journal is © The Royal Society of Chemistry.)

Exploring the rich coordination chemistry of Ce, here we report two new entries in the emerging category of hydroxamate-based metal-organic frameworks (MOFs). The two Ce-hydroxamate MOFs exhibited different band structures and photoelectrochemical properties based on their respective coordinative environments and overall structures, leading to varied H 2 generation performances.

Effective activation of CO 2 is a prerequisite for efficient utilization of CO 2 in organic synthesis. Precisely controlling the interfacial events of solids shows potential for activation. Herein, defect-enriched CeO 2 with constructed interfacial frustrated Lewis pairs (FLPs, two adjacent Ce 3+ ···O 2- ) effectively activates CO 2 via the interactions between C/Lewis basic lattice O 2- and the two O atoms in CO 2 /two adjacent Lewis acidic Ce 3+ ions. Selective cyclic carbonate production from a catalytically tandem protocol of olefins and CO 2 is used to demonstrate FLP-inspired CO 2 activation.

Extensive applications of noble metals as heterogeneous catalysts are limited by their global reserve scarcity and exorbitant price. Identifying the intrinsic active nature of a catalyst benefits the designing of catalysts with trace amounts of noble metals; these catalysts display better or comparable overall catalytic efficiency than their heavily loaded counterparts. Herein, systematic studies on Pd dispersion and surface properties of a series of Pd/CeO 2 catalysts for styrene hydrogenation showed that high Pd dispersion and surface abundant defects of the catalysts are essential to realize superior activity. Highly dispersed subnanometric Pd clusters on porous nanorods of ceria with a large surface Ce 3+ fraction of 27.4%, high Pd dispersion of 73.6%, and low Pd loading of 0.081 wt% delivered a very large turnover frequency of 103 233 h -1 based on each exposed Pd atom for styrene hydrogenation at 1.0 MPa H 2 and 30 °C. Experimental data, kinetic analysis, and density functional theory calculations revealed that the highly dispersed Pd shows a low affinity for styrene and provides more exposed Pd sites for hydrogen activation. The surface abundant defects (oxygen vacancy) of Pd/CeO 2 catalysts can enrich the electron density of Pd, improve its capability for H 2 dissociation and lower the affinity of styrene for Pd.