Bo Wu

Photothermal catalysis under mild conditions offers a promising approach for converting CO2 into value-added chemicals. Herein, we propose a strategy to achieve atomic dispersion of Ni on a low-valence metal oxide (MnO), enabling the Ni species to maintain a stable atomically dispersed state under reducing atmospheres (NiAD/MnO). In comparison, the Ni atoms anchored on high-valence MnO2 go through high-temperature reduction aggregation and sintering due to the crystal phase transformation of the support (NiNP/MnO). In the photothermal reverse water–gas shift (RWGS) reaction, NiAD/MnO achieved a CO production rate of 9.9 mmol g–1 h–1 with 99.9% CO selectivity (410 °C), far exceeding the performance of NiNP/MnO. Transient experiments and in situ spectroscopic characterization revealed that the photothermal RWGS reaction proceeds via a redox mechanism mediated by axial oxygen atoms coordinated with Ni. Theoretical calculations further demonstrated that light irradiation boosted the CO2 hydrogenation via effectively reducing the energy barrier for *CO desorption on NiAD/MnO.

In the reverse water–gas shift (RWGS) reaction, Pd-based catalysts generally exhibit a high CO2 hydrogenation activity and a low CO selectivity due to the competitive methanation reaction. In this work, cesium (Cs), an alkali-metal promoter with strong basicity, is introduced to modify Pd/γ-Al2O3 catalysts for improving CO2 activation and suppressing CH4 formation. The optimized Pd(1)-Cs(16)/γ-Al2O3 catalyst achieves a CO2 conversion of 65.07% at 600 °C, approaching thermodynamic equilibrium, and 100% CO selectivity. The introduction of Cs significantly modifies both the support and the Pd sites. The Cs species on γ-Al2O3 increase the density of surface basic sites, enhancing the CO2 adsorption and activation. Meanwhile, the Cs influences the Pd dispersion and increases the electron density of Pd, suppressing the formation of CH4. Operando ME-DRIFTS/IR reveals that carbonate, bicarbonate, and formate species are the key surface intermediates. It is speculated that the RWGS reaction over Pd(1)-Cs(16)/γ-Al2O3 follows a formate-mediated associative interfacial pathway, in which carbonate/bicarbonate species are hydrogenated into formate by Pd-derived hydrogen and subsequently converted to CO. This work provides mechanistic guidance for designing highly selective Pd-based RWGS catalysts.

High oxygen vacancy (O _v )-rich nitrogen carriers are developed via the synergy between plasma and oxygen carriers, significantly enhancing NH ₃ yield.

This study combines OES identification of reactive species, kinetic modeling of their concentrations, and mechanistic schematics to elucidate the mechanism of N ₂ activation and NH ₃ formation on plasma-coupled Ni catalysts.

Strategies for avoiding scaling relations of ammonia synthesis on the transition metal catalysts are reviewed. The green plasma ammonia processes on N ₂ and H ₂ /H ₂ O are emphasized.