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Electro‐chemically reducing CO2 in a highly acidic medium is promising for addressing the issue of carbonate accumulation. However, the hydrogen evolution reaction (HER) typically dominates the acidic CO2 reduction. Herein, we construct an efficient electro‐catalyst for CO formation based on a core‐shell structure, where nitrogen‐doped Ni nanoparticles coexist with nitrogen‐coordinated Ni single atoms. The optimal catalyst demonstrates a significantly improved CO faradaic efficiency (FE) of 96.7 % in the acidic electrolyte (pH=1) at an industrial‐scale current density of 500 mA cm−2. Notably, the optimal catalyst maintains a high FE of CO exceeding 90 % (current density=500 mA cm−2) in the electrolyte with a wide pH range from 0.67 to 14. In‐situ spectroscopic characterization and density functional theory calculations show that the local electron density of Ni‐N‐C sites is enhanced by N‐doped Ni particles, which facilitates the formation of *COOH intermediate and the adsorption of *CO. This study demonstrates the potential of a hybrid metal/Ni‐N‐C interface in boosting acidic CO2 electro‐reduction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Low temperature TEA-sensing SnS 2 /MnS microflowers are originally fabricated. • DFT simulation shows the transformation from semiconductive to metallic nature. • SnS 2 /MnS-3 % exhibits high responses of 17.85/23.67 to 100 ppm TEA at 30/40 ℃. • The enhanced metallicity plays a vital role of the enhanced gas-sensing behavior. • New strategy for gaining effective sulfide RT gas-sensing materials is presented. The development of low-temperature SnS 2 -based sensitive elements with unique surface adsorption and transport regulation for triethylamine (TEA) has always been an intractable challenge. In the present work, ultrathin SnS 2 /MnS microflowers with enhanced metallicity have been prepared by a facile one-step hydrothermal method, which is especially beneficial for achieving superior TEA-sensing performance under room temperature (RT) condition. Compared with pure SnS 2 , the SnS 2 /MnS-3 % can obviously exhibit higher responses of 17.85 and 23.67, faster response/recovery times of 165/506 and 156/344 s, and the enhanced gas selectivity and stability to 100 ppm TEA at 30 and 40 ℃, respectively. Taking account of density functional theory (DFT) calculation, the transformation of SnS 2 -based sensors from semiconductive to metallic nature plays a critical role of the enhanced gas-sensing behavior with the increased gas molecules absorption and electron transport efficiency, which can provide a new strategy for constructing novel and effective sulfide RT gas-sensing composites. [ABSTRACT FROM AUTHOR]

[Display omitted] • In situ growth of porous WO 3 /FeWO 4 hierarchical structure is originally obtained. • The distribution of p-n heterojunctions is dependent on the content of MIL-101. • The optimal operating temperatures to n-butanol can be reduced from 220 to 25 °C. • Efficient heterojunction interfaces gain surface electronic structure modulation. • A strategy of novel room temperature n-butanol-sensing performance is presented. This study originally reports the in-situ construction of porous WO 3 /FeWO 4 ribbon-like hierarchical composites with unique and intense heterojunction interface behavior and the enhanced adsorption and carrier transport capability for effectively detecting n-butanol at room temperature. The introduction of different adding amounts of MIL-101 plays the key role of the morphological evolution of WO 3 -based microstructures with the well-distributed nanoparticles in situ growth on the surface by a facile electrospinning and subsequent calcination process. Compared with pristine WO 3 , a sharp and useful reduction of the optimal operating temperature from 220 to 25 °C can be observed as the Fe component increasing, mainly owing to the inverted p-type gas sensitive response caused by the controllable variable of FeWO 4 phase in the multiple effective WO 3 -FeWO 4 heterojunctions. The optimal WO 3 /FeWO 4 composites can display the highest response of 12.3 and a relatively short response/recovery times of 110/140 s to 100 ppm n-butanol at 25 °C, together with the superior gas selectivity, repeatability, humidity and long-term stability. Density functional theory (DFT) simulation is employed for verifying the significant adsorption interaction and charge transfer between n-butanol molecule and WO 3 /FeWO 4. Regular distribution of WO 3 -FeWO 4 heterojunction interfaces can not only determine the collaborative modulation of electronic structures, but also provide the efficient surface/interface transport mechanism for MIL-101 induced one-dimensional (1D) hierarchical ribbons. Actually, the integrated gas-sensitive components based on WO 3 /FeWO 4 composites exhibit the rapid response characteristic under room temperature condition and provide a friendly strategy of optimizing the practical detection of ppm-level n-butanol for other inorganic heterogeneous sensors. [ABSTRACT FROM AUTHOR]

Glucose hydrogenation to sorbitol is a vital industrial reaction for the utilization of biomass. Generally, hydrogenation is catalyzed by the inexpensive Raney Ni catalyst which has good catalytic but suffers from poor stability and side reaction，and the mechanisms of glucose hydrogenation on Raney Ni surfaces is also unclear. This study combines density functional theory calculations, ab initio molecular dynamics simulations (AIMD), and experiments to reveal the nature of glucose hydrogenation on the (111), (200), and (220) surfaces of Ni catalyst. The DFT calculation results show that the (111) and (200) surfaces of Raney Ni are favorable for hydrogenation with 111-η2, 200-η2–1, 200-η2–3 adsorption configurations and adsorption energy is closely related to the rate-determining step. Furthermore, in-situ IR analysis and AIMD calculation confirm the existence of 111-η2 structure in hydrogenation, while electronic analysis demonstrates that improving the alignment of the nickel surface's d orbitals with the -C O bond's π orbitals can enhance both the adsorption and catalytic hydrogenation activity. In addition, the (220) surface is found to be responsible for the dehydrogenation of cyclic-glucose, and decreasing the percentage of the (220) surface and increasing the reaction temperature appropriately may be effective in inhibiting the side reaction. This paper not only reveals the nature of Raney Ni catalyzed glucose hydrogenation but also lights the direction for the design of highly efficient nickel-based catalysts. [Display omitted] • DFT, AIMD calculations and in-situ IR are combined to uncover the mechanism of open-ring hydrogenation process. • 111-η2 adsorption configuration is the most likely structure on Ni (111). • Electronic analysis unveils the nature that E RDS is positively correlated with E ads on Ni surfaces. • Ni (220) surface is responsible for dehydrogenation side reaction. [ABSTRACT FROM AUTHOR]

• Gas sensing ability of CuCrO 2 to TEA is studied experimentally and theoretically. • Active sites of CuCrO 2 to TEA are determined by in-situ heating spectrum technique. • TEA is adsorbed to Cr CUS and dehydrogenated on Cu and O generating sensing signal. • CuCrO 2 nanorods are excellent to selectively detect TEA at low temperature. Metal oxide semiconductors are recognized as an excellent underlying substance for the assembly of gas sensors to detect the volatile organic compounds in industry or healthcare, but are constrained by their low selectivity and high operation temperature. In the present paper, we present a nanostructured p-type delafossite CuCrO 2 , synthesized by the hydrothermal method, that provides a high selectivity, stability and high dynamic response to triethylamine at a low temperature of 140 ℃. In-situ heating spectrum analysis and systematic gas sensing tests with the assistance of first principles calculations based on the density functional theory demonstrate that this ternary oxide takes a unique synergy mechanism for gas sensing process, rather than the ionosorption effect of ambient oxygen. It starts with the adsorption of gas molecules to the unsaturated coordinative metal sites of Cr, which is then followed by the dehydrogenation on Cu resulting in the formation of oxygen vacancies. This gas sensing mechanism successfully explains the extraordinary properties of CuCrO 2 nanoparticles as a triethylamine sensor. This work delivers an exploratory approach to the assigned interaction of gas molecules and the sensitive layer at atomic scale, which provides ways to design and develop more advanced gas sensors for other material systems. [ABSTRACT FROM AUTHOR]