Selective hydrogen production from formic acid decomposition over Mo carbides supported on carbon materials
Selective hydrogen production from formic acid decomposition over Mo carbides supported on carbon materials
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碳材料负载碳化钼催化甲酸选择性分解制氢
DOI：
10.1039/d0cy01088j
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发表时间：
2020-10-21
影响因子：
5
通讯作者：
Rodriguez-Ramos, I
中科院分区：
文献类型：
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作者：
Carrales-Alvarado, D. H.;Dongil, A. B.;Rodriguez-Ramos, I
用活性炭负载碳化钼和两种高比表面积石墨H-200（200 m（2）g（-1））和H-400（400 m（2）g（-1））研究了甲酸分解制氢。特别注意的是Mo负载的效果。该催化剂使用CH 4和H-2的混合物在高达700摄氏度的温度下原位制备。在这些条件下，渗碳基本完成。我们观察到，载体影响所获得的MoxC相，使得似乎缺陷碳的比率影响该相。然而，对于这些材料，C/Mo比不影响所获得的晶相。通过XRD表征显示，虽然在活性炭上和在H-200上获得β-Mo 2C相，但是相比之下，在H400上获得MoOxCy。这些催化剂在190-250 ℃的温度范围内对甲酸分解达到100%转化率，并且在这些温和条件下也具有高度选择性，CO2选择性值在85.096.5%的范围内。在活性炭上负载10重量% Mo时获得最佳结果，其达到96.5%的H-2选择性。此外，在废催化剂上观察到钼相的变化。在反应过程中的一些氧化还原转变负责β-Mo 2C转化为碳氧化物MoOxCy。总之，催化性能的结果表明，在所研究的条件下，β-Mo 2C相比MoOxCy更活性、选择性和稳定性。
The decomposition of formic acid to obtain hydrogen has been studied using molybdenum carbides supported on activated carbon and two high surface area graphites, H-200 (200 m(2) g(-1)) and H400 (400 m(2) g(-1)). Particular attention is paid to the effect of Mo loading. The catalysts were prepared in situ using a mixture of CH4 and H-2 at a temperature of up to 700 degrees C. Under these conditions, carburization was mostly complete. We observed that the support influenced the MoxC phase obtained so that it seems that the ratio of defective carbon influences the phase. However, for these materials the C/Mo ratio did not influence the obtained crystal phase. Characterization by XRD showed that while the beta-Mo2C phase was obtained over activated carbon and over H-200, in contrast, MoOxCy was obtained over H400. These catalysts reached 100% conversion on formic acid decomposition at temperatures in the range of 190-250 degrees C and were also highly selective under these mild conditions, with values for CO2 selectivity in the range of 85.096.5%. The best results were achieved over a 10 wt% Mo loading on activated carbon that reached 96.5% selectivity to H-2. Also, changes in the molybdenum phases were observed on the spent catalyst. Some redox transformations during reaction were responsible for the transformation of beta-Mo2C into oxycarbide MoOxCy. In summary, the results of the catalytic performance indicated that the beta-Mo2C phase was more active, selective and stable than MoOxCy under the studied conditions.