Optimizing Mo2C-based catalytic system for efficient CO2 conversion and CO selectivity through carbon-nitrogen supporting and potassium promotion

• Published in: Journal of environmental chemical engineering 2024-10, Vol.12 (5), p.113380, Article 113380
• Main Authors: Galallah, Abdelrazek G., Albolkany, Mohamed K., Rashed, Ahmed E., Sadik, Wagih, El-Demerdash, Abdel-Ghaffar, El-Moneim, Ahmed Abd
• Format: Article
• Language: English
• Subjects: CO production; CO2 utilization; MOF-derived catalyst; Molybdenum carbide catalyst; Potassium promotion; RWGS
• ISSN: 2213-3437
• DOI: 10.1016/j.jece.2024.113380

Preparing highly active, stable, and selective catalysts for the reverse water gas shift (RWGS) reaction is challenging because of the aggregation of the active catalyst at high RWGS reaction temperatures and deactivation of the active sites. Herein, we present a comparative evaluation and optimization of a molybdenum carbide system using a carbon-nitrogen (CN) support and alkali promotion. Hydrothermally prepared MoO3 nanorods were carburized at 700 °C using H2:CO (4:1) to prepare unsupported Mo2C, while CN-supported Mo2C (Mo2C@CN) was prepared using Mo-based metal-organic framework (Mo-MOF) as a sacrificial template. The as-prepared Mo2C@CN catalytic system was found to be highly active in the RWGS reaction in comparison with the unsupported Mo2C, where CO2 conversion percentage was around 76 % at 700 °C, combined with high CO selectivity (87 %) and very reduced CH4 selectivity (2 %). The addition of potassium as a promoter enhanced CO selectivity (99 %). The active catalyst performance was stable during the catalysis process and for up to 100 h, which imposes the effect of the CN support in preventing the aggregation of Mo2C and keeping its active sites in direct contact with the reactant. This work presents an effective strategy for improving the active catalyst dispersion and reducibility in synergy with the promoter effect to optimize the RWGS reaction output. •Well-dispersed Mo2C on carbon-nitrogen support was prepared using MOF as a sacrificial template for RWGS reaction.•High CO2 conversion (76 % at 700 °C) using Mo2C supported on carbon-nitrogen in comparison with unsupported Mo2C (68 %).•Improved CO selectivity (99 %) on potassium-promoted MO2C@CN over a wide catalytic temperatures range.•Very stable catalytic performance of the developed catalytic system even after 100 hours on stream.