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The cost‐effectiveness and excellent performance of conductive‐carbon‐supported Ni‐based electrocatalysts make them attractive materials for hydrogen oxidation and evolution reactions. However, they were previously unused in gas‐phase hydrogenation reactions. In this work, we have expanded the applicability of commercially available advanced Ni/C, NiMo/C and NiRe/C materials from electrocatalysis to heterogeneous catalysis of CO2 methanation. Our catalytic testing efforts indicate that the monometallic Ni/C material demonstrates the best CO2 methanation properties, achieving an excellent CO2 conversion of 83 % at 400 °C with nearly complete selectivity to CH4 of 99.7 %, plus exhibiting intact performance during 90 h of time‐on‐stream testing. Such catalytic properties are among the highest reported to date among carbon‐supported Ni‐based methanation catalysts. Excellent performance of Ni/C stems from the good dispersion of the Ni nanoparticles over N‐containing carbon support material. [ABSTRACT FROM AUTHOR]

Nickel phosphide is an emerging low-cost, earthabundant catalyst that can efficiently reduce water to generate hydrogen. However, the synthesis of nickel phosphide catalysts usually involves multiple steps and is laborious. Herein, a convenient and straightforward approach to the synthesis of a three-dimensional (3D) self-supported biphasic Ni5P4- Ni2P nanosheet (NS) array cathode is presented, which is obtained by direct phosphorization of commercially available nickel foam using phosphorus vapor. The synthesized 3D Ni5P4-Ni2P-NS array cathode exhibits outstanding electrocatalytic activity and long-term durability toward the hydrogen evolution reaction (HER) in acidic medium. The fabrication procedure reported here is scalable, showing substantial promise for use in water electrolysis. More importantly, the approach can be readily extended to synthesize other selfsupported transition metal phosphide HER cathodes. [ABSTRACT FROM AUTHOR]

The semi-hydrogenation of acetylene (C 2 H 2 + H 2 = C 2 H 4 , Δ H = −172 kJ mol−1) is a well-studied reaction that is important for purification of ethylene, C 2 H 4 , feed used in polyethylene production. Pd-based catalysts are most commonly used to remove acetylene from ethylene feed prior to Ziegler–Natta polymerization because acetylene is a poison for Ziegler–Natta catalysts. New applications of the analogous catalytic processes, with similar requirements for the conversion and selectivity, are considered for the storage of H 2 within the context of the H 2 economy. Here, a combination of experimental and theoretical studies was employed to explore the performance of synthesized Pd nanoparticles and the feasibility of using computational modelling for predicting their catalytic properties. Specifically, a model 5%Pd/Al 2 O 3 nanocatalyst was successfully synthesized using high-throughput flame spray pyrolysis (FSP) method. As a catalyst for acetylene semi-hydrogenation, the material shows high conversion of 97%, a modest selectivity of 62%, and a turnover frequency of ethylene formation of 5 s−1. The experimental data were further supported by computational modelling of catalytic properties. Results of microkinetic simulations, based on parameters obtained from DFT calculations, over a Pd 30 /Al 2 O 3 (100) model system were correlated with experiments. The insights from this direct comparison of theory and experiments provide indications for future improvements of the theoretical predictions and for novel types of materials with improved catalytic properties. Image 1 • High-throughput flame spray pyrolysis was used for the synthesis of Pd/Al 2 O 3. • The catalyst offered acetylene conversion of 97% and selectivity to ethylene of 62%. • The experimental results are supported by DFT and microkinetic simulations. [ABSTRACT FROM AUTHOR]

The development of novel cost-efficient, high-performing catalysts for CO 2 methanation that are active at low temperatures can be optimized through the understanding of the reaction mechanism on different materials. A series of Ni-based catalysts supported on CeO 2 and carbon/CeO 2 composites was investigated, showing that Ni nanoparticles supported on a carbon/CeO 2 composite with a 50:50 wt ratio and on pure CeO 2 have excellent low-temperature activity and achieve up to 87% CO 2 conversion with full selectivity towards CH 4 at 370 °C. Importantly, meaningful insights on the reaction mechanism were gathered for the different types of materials by using the emerging ME−PSD−DRIFTS technique. The study of the rate of formation/consumption of the various intermediates showed that the CO 2 methanation reaction follows a combination of the CO and formate pathways in the case of Ni on pure CeO 2 ; however, in the case of Ni on the carbon/CeO 2 composite, it follows only the formate pathway. [Display omitted] • In situ ME-PSD-DRIFTS was used to gather mechanistic insights for CO2 methanation. • The analytical challenges of the dynamic reaction environment were overcome. • Different intermediate steps were observed in the two different Ni catalysts. • Carbon−CeO2 composite was successfully employed, reducing the use of CeO2 by 50%. • Newly developed catalysts demonstrated excellent XCO2 ≈ 87% and SCH4 ≈ 100% at 370 °C. [ABSTRACT FROM AUTHOR]