Direct synthesis of H2O2 in AuPd coated micro channels: An in-situ X-Ray absorption spectroscopic study

High H2O2 Utilization Promotes Selective Oxidation of Methane to Methanol at Low Temperature

“…A relative mild decomposition of H 2 O 2 to •OH radicals can therefore be achieved by tuning the Pd-to-Au ratio. Similar results have been reported in the direct synthesis of H 2 O 2 from H 2 and O 2 (Kanungo et al, 2019). According to the literature, a high concentration of •OH radicals facilitates the disproportionation to H 2 O and O 2 via a hydrogen transfer mechanism (Plauck et al, 2016).…”

“…In terms of Pd-to-Au ratios, the addition of Au into Pd can dilute the surface to reduce the number of sites for O-O scission. Besides, the electron transfer between Au and Pd also alter the adsorption strength of H 2 O 2 with metal surface (Kanungo et al, 2019). A relative mild decomposition of H 2 O 2 to •OH radicals can therefore be achieved by tuning the Pd-to-Au ratio.…”

Dynamic structural changes of supported Pd, PdSn, and PdIn nanoparticles during continuous flow high pressure direct H2O2synthesis

“…9 The difference is attributed to the effect of ethanol solvent which provides net reducing environment since it is a dominating reagent in the system, even if O 2 is dissolved. Full reduction of Pd NPs in alcohols was evidenced previously by Grunwaldt et al 34 and, in relation to H 2 O 2 synthesis in methanol, also by Kanungo et al 8 While surface chemisorbed O was visible in aqueous solution, 9 the same Pd NPs were fully reduced in a separate experiment with pure ethanol (even containing dissolved O 2 ). 35 The other contributing factor, as compared to our previous study, 9 is that NPs of larger size were used in this work which results in a very small fraction of surface Pd (<1%) 36 (almost invisible for conventional XAS) and could further explain the inability to observe surface oxygen in this study.…”

“…1,2 In addition, new and intrinsically safe concepts, that make use of membrane reactors 6,7 and electrochemical H 2 O 2 production, 3 have emerged. Recently, operando studies of the catalysts for H 2 O 2 production were reported by eliminating the explosion hazard by using thin capillaries as in situ reactors 8 or dissolving H 2 and O 2 at high pressures in separate liquid streams. 9 Platinum-group metal nanoparticles (NPs) are presently the most active catalysts for the direct H 2 O 2 synthesis.…”

Looking for the “Dream Catalyst” for Hydrogen Peroxide Production from Hydrogen and Oxygen

“…In 2019, in situ X-Ray Absorption Spectroscopy was used [69] for an investigation on Pd and Pd-Au silica supported samples during the direct synthesis of hydrogen peroxide in a high-pressure gas-liquid-solid microreactor. The authors concluded that the absence of Pd-hydride in the bimetallic catalysts reduces further hydrogenation of hydrogen peroxide to water, thus increasing selectivity.…”