CO-resistant hydrogenation over noble metal/α-MoC catalyst
Xuan Liang1, Xiangxin Jin2, Shixiang Yu1
1Beijing National Laboratory for Molecular Science, New Cornerstone Science Laboratory, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China.
A novel palladium on molybdenum carbide (Pd/α-MoC) catalyst efficiently hydrogenates liquid organic hydrogen carriers using crude hydrogen, overcoming CO poisoning. This breakthrough enhances hydrogen purification and utilization processes.
Area of Science:
- Catalysis
- Materials Science
- Chemical Engineering
Background:
- Liquid organic hydrogen carriers (LOHCs) offer a promising strategy for hydrogen storage and transport.
- Purification of crude hydrogen is a significant bottleneck in LOHC-based hydrogen utilization.
- Catalyst poisoning by impurities like carbon monoxide (CO) severely limits process efficiency.
Purpose of the Study:
- To develop a novel catalyst for efficient hydrogenation of N-LOHCs using crude hydrogen feeds.
- To overcome the challenge of CO poisoning in crude hydrogen streams.
- To investigate the mechanism behind enhanced catalytic activity and CO resistance.
Main Methods:
- Development of a palladium supported on alpha-molybdenum carbide (Pd/α-MoC) catalyst.
- Testing hydrogenation activity under crude hydrogen feeds with high CO concentrations (>5 vol%) below 150°C.
- Utilizing water as a solvent to leverage the low-temperature water-gas shift (WGS) reaction.
- Comparative analysis with traditional Pd-based catalysts and Pt/α-MoC.
Main Results:
- The Pd/α-MoC catalyst demonstrated 1-2 orders of magnitude higher activity compared to traditional Pd catalysts.
- Efficient hydrogenation was achieved even with CO concentrations exceeding 5 vol% at temperatures below 150°C.
- The catalyst showed CO resistance in model crude hydrogen streams containing CO, CO2, and CH4.
- Water as a solvent facilitated hydrogenation via the WGS reaction, mitigating CO poisoning.
- Positively charged Pd species were found to suppress undesirable H2 formation, enhancing performance.
Conclusions:
- Pd/α-MoC is a highly active and CO-resistant catalyst for LOHC hydrogenation using crude hydrogen.
- The catalyst's performance is significantly improved by water-mediated WGS reaction and specific electronic properties of Pd species.
- This development offers a viable pathway to reduce costs and streamline hydrogen purification and utilization.
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