Direct synthesis of hydrogen peroxide over supported Pd catalysts: Turning to dense CO2 as an alternative solvent

•An alternative approach for H2O2 direct synthesis in dense CO2 was investigated.•Highly active and selective Pd-supported batch catalysts were synthesised.•Decreased catalyst performance in dense CO2 in batch mode was observed.•Continuous operation in a micro reactor with dense CO2 improved catalyst activity.

An approach for the direct synthesis of hydrogen peroxide with CO2 as solvent has been explored. Both batch and continuous experiments have been performed. The activity of self-prepared Pd-supported catalysts has been verified leading to high productivity of up to 132 gH2O2 gPd−1 h−1132 gH2O2 gPd−1 h−1 in batch with selectivities of up to 70%. However, the use of dense CO2 in batch set back catalyst activity leading to the formation of H2O as the only product. For the continuous process in dense CO2 increased performance in terms of productivity with up to 26 gH2O2 gPd−1 h−126 gH2O2 gPd−1 h−1 with low selectivity were achieved.

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