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Solid Oxide Electrolysis Cell (SOEC) is an efficient green hydrogen production technology, which is a reverse of Solid Oxide Fuel Cell (SOFC). In this paper, an anode-supported SOEC produced via multi-layer organic co-tape casting with co-sintering process is investigated for high temperature steam electrolysis, carbon dioxide electrolysis, and co-electrolysis. SOEC cathode must maintain its electrocatalytic activity in a high temperature and humidity condition. La 0.75 Sr 0.25 Cr 0.5 Mn 0.5 O 3-δ (LSCM) is one of the most promising cathode materials because of its superior electrocatalytic ability and redox stability. The anode-supported structure of electrolysis cell reduces ohmic resistance obviously and LSCM cathode exhibits good catalytic performance. To evaluate the performance of co-electrolysis, a continuous voltage of 1 V is applied for 256 h with 60% H 2 O and 40% CO 2 at 750 °C. The anode-supported SOEC with LSM((La 0.8 Sr 0.2) 0.95 Mn 0.5 O 3-δ)/LSM-YSZ(Zr 0.92 Y 0.08 O 2-δ)/YSZ/LSCM structure has good electrochemical performance and durability under co-electrolysis conditions combined with the distribution relaxation of time analysis of impedance spectra. • An anode-supported SOEC was fabricated by multi-layer organic co-tape casting. • The cell's structure was LSM/LSM-YSZ/YSZ/LSCM. • The anode-supported SOEC with LSCM cathode was used for co-electrolysis. • LSCM cathode showed good catalytic performance and stability of the structure. • The current density is about 2 A cm−2 after constant electrolysis 200 h. [ABSTRACT FROM AUTHOR]

[Display omitted] • Depressurization followed CO 2 -N 2 injection for CH 4 recovery and CO 2 sequestration. • Effect of MH dissociation ratio on subsequently mixed hydrate formation. • CH 4 hydrate re-formation and dissociation occurred depending on CH 4 hydrate left. • CO 2 hydrate formation depended on the CH 4 left in both gas phase and hydrate phase. • Increasing CH 4 production decreased the CO 2 sequestration and hydrate restoration. Natural gas hydrates (NGHs) buried below the seafloor are globally abundant, energy-dense, and essential to the world's future energy mix. The combination of depressurization and CO 2 -N 2 injection processes for NGHs recovery has been identified as an environmental method to harvest energy, CO 2 sequestration, and to maintain the mechanical stability of sediment. In this regime, partial CH 4 was produced by depressurization followed by CO 2 -N 2 injection to form CH 4 -CO 2 -N 2 mixed hydrate (Mix-H). In this study, a series experiments were designed to examine the key factors in the depressurization process (i.e. bottom hole pressure BHP and CH 4 production ratio) on the subsequent processes of Mix-H formation, CO 2 sequestration and hydrate restoration. It was observed that Mix-H formation occurred in all cases, but the final amount of Mix-H were all lower than the initial amount of MH before depressurization. Particularly, the formation of CO 2 /N 2 hydrate in Mix-H is positively correlated with the amount of remaining CH 4 in the combined phases of gas and hydrate after depressurization. The formation of CH 4 hydrate in Mix-H during the reformation process occurred in five cases when MH dissociation ratio (D MH) reaches above 45.1 % during depressurization. MH was only observed to dissociate continuously after CO 2 /N 2 injection when D MH is low at 30.8 %, which indicates possible "CH 4 -CO 2 replacement reaction". Overall, increasing CH 4 production at the same BHP decreases the CO 2 sequestration and hydrate restoration. We first verified the feasibility of the combination method for synergistic CH 4 recovery and CO 2 sequestration in marine conditions. The experimental results provide possible guidance on the optimal design of the coupled processes and shed light on the relationship between CH 4 recovery and CO 2 sequestration that need to be wholistically balanced. [ABSTRACT FROM AUTHOR]

• A Cu based perovskite photocatalyst toward CO 2 conversion was fabricated by consecutive in-situ exsolution/redispersion strategy. • The uniformly dispersed Cu site and modified band structure is beneficial for enhancing light absorption and photocatalytic activity. Excessive exploitation and depletion of fossil fuels have led to the escalation of CO 2 emissions, which are responsible for global climate deterioration. Cu-based solid catalysts can transform CO 2 into various hydrocarbons via a sustainable photocatalytic pathway. Herein, we fabricated a Cu-decorated LaFeO 3 photocatalyst using a sequential in situ exsolution (in H 2)/redispersion (in N 2) strategy. The dispersion of Cu was significantly enhanced (∼3 times), i.e., from 13.8 % (exsolved) to 41.4 % (redispersed). The combined theoretical and experimental results confirmed the successful formation of uniformly dispersed Cu active sites for efficient CO 2 adsorption and photocatalytic conversion. The enhancement of light absorption and manipulation of the band structure were also collectively achieved, offering an optimized catalyst involving superior CO and CH 4 production compared to its counterparts. In addition, photocatalytic water splitting was significantly suppressed, suggesting high selectivity of the photocatalytic pathway. This study offers a new perspective on the design principle of photocatalysts for selective CO 2 conversion. [ABSTRACT FROM AUTHOR]