Promotion effects of Pd on tungsten carbide catalysts: physiochemical properties and cellulose conversion performance

Abstract

A multi-functional catalyst, which is able to perform both retro-aldol reactions followed by hydrogenation, is required to convert cellulose into value-added chemicals such as ethylene glycol (EG) in a one-pot reaction.

Elucidating the Role of Ni(Pd) in Ni(Pd)-Mo2C/Carbon Catalysts for the Hydrodeoxygenation of Dibenzofuran and Bio-Oil

“…60, 180, and 380 °C, respectively. Similarly, on the Pd-Mo 2 C/ABC catalyst, 3 peaks at 90, 150, and 300 °C were evident (Figure c), suggesting that both Ni and Pd enhanced O removal from the Mo 2 C surface at low temperature, presumably by increasing H 2 dissociation. , As reported in Table , the total H 2 consumption per mol of metal promoter plus Mo was lower on the Ni-Mo 2 C/ABC catalyst compared to the Pd-Mo 2 C/ABC and Mo 2 C/ABC catalysts. The H 2 consumption at low temperature (≤200 °C; steps I and II) only occurred on Ni- or Pd-promoted Mo 2 C and was lowest on the Ni-Mo 2 C/ABC catalyst (2 mmol H 2 /mol Ni vs 16 mmol H 2 /mol Pd in step I; 2 mmol H 2 /mol metal vs 4 mmol H 2 /mol metal in step II; see Table ).…”

“…Similarly, on the Pd-Mo 2 C/ABC catalyst, 3 peaks at 90, 150, and 300 °C were evident (Figure 2c), suggesting that both Ni and Pd enhanced O removal from the Mo 2 C surface at low temperature, presumably by increasing H 2 dissociation. 36,37 As reported in 2). Note that there was no H 2 consumption when the same TPR measurement was done on a fresh Ni-Mo 2 C/ABC catalyst without O 2 passivation, as shown in Figure S2a.…”

“…A number of studies have explored how the presence of a second metal tunes the properties of Mo 2 C catalysts. − Among numerous promoters, Ni and Co are frequently used in Mo-based catalysts. − , Other metals have also been reported as promoters of carbide catalysts. For example, Leal et al . reported that Pd was able to produce a cleaner W 2 C surface by hindering carbon deposition during the carburization process, which in turn enhanced catalyst performance in cellulose conversion.…”

“…For example, Leal et al . 36 reported that Pd was able to produce a cleaner W 2 C surface by hindering carbon deposition during the carburization process, which in turn enhanced catalyst performance in cellulose conversion. From this, one can conclude that surface properties of Mo 2 C can be altered by the addition of a second metal, which in turn impacts the catalyst activity and stability.…”

Preparation of Carbon‐Supported Tungsten Carbides: Comparative Determination of Surface Composition and Influence on Cellulose Transformation into Glycols

“…Examples of glycols formation from cellulose are reported in the literature. [1][2][3] From these reports it appears that (1) Brønsted acidity may come from the applied hydrothermal conditions (200-260 °C) generating H 3 O + species; (2) Lewis acidity may be due to metal species, particularly, and excepting few examples, [4][5][6][7][8][9] tungsten species; (3) hydrogenating metal catalyst is most often Ni, although other metals [10][11][12][13][14][15][16][17][18] have been proposed in recent studies. In most of the reported systems, both the W species and hydrogenating metal are supported acting as heterogeneous catalysts.…”