Oxygen Vacancy Enhanced Proton Transfer to Boost Carbamate Decomposition Kinetics with Tunable Heterostructure Ni/NiO

Catalytic carbamate decomposition is a feasible option for reducing the heat duty of amine solvent regeneration during the chemisorption of CO2 capture; advanced material with excellent proton transfer and exchange performance is crucial to boost the decomposition kinetics in an alkaline environment. Here, we prepared magnetic heterostructure Ni/NiO nanocatalysts with tunable Ni(0) nanoparticles and NiO support. The heterointerface of the proposed materials creates abundant surface oxygen vacancies (OVs) and offers abundant reactive active sites ascribed to the special electron transfer scheme of Ni0–NiO. The generated surface hydroxyls and unsaturated coordinated Ni, respectively, provide transferable protons and electrons, involved in the deprotonation of RNH3+ and C–N break of RNHCOO–. Thus, the obtained nanomaterials achieved considerably improved CO2 desorption of up to 3 mmol/min for a CO2-saturated monoethanolamine solvent, representing a substantial (approximately 50%) increase over the catalyst-free case. The reinforcement mechanism of OV generation by the Ni/NiO heterostructure and the induced proton transfer were revealed through in situ spectroscopic measurement and theoretical calculations. The results verified that the OVs stimulate the production of surface hydroxyls and water-assisted proton hopping, providing an advantageous condition for carbamate decomposition

Oxygen Vacancy Enhanced Proton Transfer to Boost Carbamate Decomposition Kinetics with Tunable Heterostructure Ni/NiO

Catalytic carbamate decomposition is a feasible option for reducing the heat duty of amine solvent regeneration during the chemisorption of CO2 capture; advanced material with excellent proton transfer and exchange performance is crucial to boost the decomposition kinetics in an alkaline environment. Here, we prepared magnetic heterostructure Ni/NiO nanocatalysts with tunable Ni(0) nanoparticles and NiO support. The heterointerface of the proposed materials creates abundant surface oxygen vacancies (OVs) and offers abundant reactive active sites ascribed to the special electron transfer scheme of Ni0–NiO. The generated surface hydroxyls and unsaturated coordinated Ni, respectively, provide transferable protons and electrons, involved in the deprotonation of RNH3+ and C–N break of RNHCOO–. Thus, the obtained nanomaterials achieved considerably improved CO2 desorption of up to 3 mmol/min for a CO2-saturated monoethanolamine solvent, representing a substantial (approximately 50%) increase over the catalyst-free case. The reinforcement mechanism of OV generation by the Ni/NiO heterostructure and the induced proton transfer were revealed through in situ spectroscopic measurement and theoretical calculations. The results verified that the OVs stimulate the production of surface hydroxyls and water-assisted proton hopping, providing an advantageous condition for carbamate decomposition

Sulfur Migration Enhanced Proton-Coupled Electron Transfer for Efficient CO₂ Desorption with Core-Shelled C@Mn₃O₄

Transforming hazardous species into active sites by ingenious material design was a promising and positive strategy to improve catalytic reactions in industrial applications. To synergistically address the issue of sluggish CO2 desorption kinetics and SO2-poisoning solvent of amine scrubbing, we propose a novel method for preparing a high-performance core–shell C@Mn3O4 catalyst for heterogeneous sulfur migration and in situ reconstruction to active –SO3H groups, and thus inducing an enhanced proton-coupled electron transfer (PCET) effect for CO2 desorption. As anticipated, the rate of CO2 desorption increases significantly, by 255%, when SO2 is introduced. On a bench scale, dynamic CO2 capture experiments reveal that the catalytic regeneration heat duty of SO2-poisoned solvent experiences a 32% reduction compared to the blank case, while the durability of the catalyst is confirmed. Thus, the enhanced PCET of C@Mn3O4, facilitated by sulfur migration and simultaneous transformation, effectively improves the SO2 resistance and regeneration efficiency of amine solvents, providing a novel route for pursuing cost-effective CO2 capture with an amine solvent