Core-shell structured CaO-Ca 9 Al 6 O 18 @Ca 5 Al 6 O 14 /Ni bifunctional material for sorption-enhanced steam methane reforming

Hydrogen Production from Coal Industry Methane

Coal industry methane is a fossil raw material that can serve as an energy carrier for the production of heat and electricity, as well as a raw material for obtaining valuable products for the chemical industry. To ensure the safety of coal mining, rational environmental management and curbing global warming, it is important to develop and improve methods for capturing and utilizing methane from the coal industry. This review looks at the scientific basis and promising technologies for hydrogen production from coal industry methane and coal production. Technologies for catalytic conversion of all types of coal industry methane (Ventilation Air Methane – VAM, Coal Mine Methane – CMM, Abandoned Mine Methane – AMM, Coal-Bed Methane – CBM), differing in methane concentration and methane-to-air ratio, are discussed. The results of studies on the creation of a number of efficient catalysts for hydrogen production are presented. The great potential of hybrid methods of processing natural coal and coal industry methane has been demonstrated.

CO2 Capture at Medium to High Temperature Using Solid Oxide-Based Sorbents: Fundamental Aspects, Mechanistic Insights, and Recent Advances

Carbon dioxide capture and mitigation form a key part of the technological response to combat climate change and reduce CO₂ emissions. Solid materials capable of reversibly absorbing CO₂ have been the focus of intense research for the past two decades, with promising stability and low energy costs to implement and operate compared to the more widely used liquid amines. In this review, we explore the fundamental aspects underpinning solid CO₂ sorbents based on alkali and alkaline earth metal oxides operating at medium to high temperature: how their structure, chemical composition, and morphology impact their performance and long-term use. Various optimization strategies are outlined to improve upon the most promising materials, and we combine recent advances across disparate scientific disciplines, including materials discovery, synthesis, and in situ characterization, to present a coherent understanding of the mechanisms of CO₂ absorption both at surfaces and within solid materials.

Enhanced Hydrogen Production from Sawdust Decomposition Using Hybrid-Functional Ni-CaO-Ca2SiO4 Materials

A hybrid-functional material consisting of Ni as catalyst, CaO as CO₂ sorbent, and Ca₂SiO₄ as polymorphic "active" spacer was synthesized by freeze-drying a mixed solution containing Ni, Ca and Si precursors, respectively, to be deployed during sawdust decomposition that generated gases mainly containing H₂, CO, CO₂ and CH₄. The catalytic activity showed a positive correlation to the Ni loading, but at the expense of lower porosity and surface area with Ni loading beyond 20 wt %, indicating an optimal Ni loading of 20 wt % for Ni-CaO-Ca₂SiO₄ hybrid-functional materials, which enables ∼626 mL H₂ (room temperature, 1 atm) produced from each gram of sawdust, with H₂ purity in the product gas up to 68 vol %. This performance was superior over a conventional supported catalyst Ni-Ca₂SiO₄ that produced 443 mL H₂ g-sawdust^-1 under the same operating condition with a purity of ∼61 vol %. Although the Ni-CaO bifunctional material in its fresh form generated a bit more H₂ (∼689 mL H₂ g-sawdust^-1), its cyclic performance decayed dramatically, resulting in H₂ yield reduced by 62% and purity dropped from 73 to 49 vol % after 15 cycles. The "active" Ca₂SiO₄ spacer offers porosity and mechanical strength to the Ni-CaO-Ca₂SiO₄ hybrid-functional material, corresponding to its minor loss in reactivity over cycles (H₂ yield reduced by only 7% and H₂ purity dropped from 68 to 64 vol % after 15 cycles).