The effect of reduction temperature and Zn doping on the catalytic activity of Pt–Al2O3 catalyst for catalytic H2/O2 recombination

The development and optimisation of highly active and stable catalysts for H 2 /O 2 recombination is crucial to ensure safe H 2 utilisation in confined environments, such as garages for H 2 -fuelled cars or underground mines, including critical applications like nuclear power plants. In this study, the development and performance of Zn-modified Pt/Al 2 O 3 catalysts for H 2 /O 2 recombination were demonstrated. The effect of the reduction temperature on Pt particle size and catalytic performance was also investigated. A series of Pt/Zn–Al 2 O 3 catalysts containing 1, 3, and 10 wt% Zn were prepared and evaluated. The BET, XRD, CO-pulse chemisorption, TPR, STEM, and EELS analyses revealed that the incorporation of Zn significantly modifies the morphology and Pt dispersion of the resulting catalysts. Catalytic tests demonstrated that a suitable Zn doping (i.e. 3 wt%) and reduction temperature (i.e. 350 °C) significantly improved both the stability (showing no deactivation) and catalytic performance (achieving high H 2 conversion). Finally, the Pt/Zn–Al 2 O 3 (3 wt% Zn) catalyst was tested in a passive autocatalytic recombiner (PAR) in 0–5 vol% H 2 /air mixtures and constant gas flow velocity of 8 m/s. A maximum H 2 conversion of 90 % was achieved during the PAR test. This confirms the potential of the Pt/Zn–Al 2 O 3 (3 wt% Zn) in real-world H 2 safety systems, such as PARs. • 1, 3, and 10 wt% Zn modified Pt/Al 2 O 3 catalysts for H 2 safety applications. • The reduction temperature of 350 °C resulted in uniform Pt particle distribution. • 3 wt% Zn addition prevented Pt particle aggregation during 500h of reaction. • No catalyst deactivation after 500 h of H 2 and O 2 recombination at 275 °C. • The maximum conversion of 90 % was achieved for Pt/Zn–Al 2 O 3 with 3 wt% Zn.