Superhydrophobic Pt–Pd/Al2O3 catalyst coating for hydrogen mitigation system of nuclear power plant

Abstract

Passive auto-catalytic recombiner (PAR) system is an important hydrogen mitigation method which has been applied in most modern light water nuclear reactors. The two challenges for the highly efficient PAR are the detrimental effect of water and poisoning by fission products. In this study, to address the two challenges, superhydrophobic Pt–Pd/Al2O3 catalyst coatings were prepared by wet impregnation method and the grafting of 1H,1H,2H,2H-perfluorooctyltriethoxysilane.The formation of a Pt–Pd intermetallic compound was confirmed by in situ diffuse reflectance infrared Fourier transform infrared spectroscopy for the Pt–Pd/Al2O3 catalyst. The Pt–Pd/Al2O3 catalyst exhibited a superior resistance of water poisoning to the monometallic catalysts. In addition, compared with the monometallic catalysts, the least influence by the iodine poisoning was observed for the Pt–Pd/Al2O3 catalyst, which is attributed to the smallest influence on the bindings of H2 and O2 on the Pt–Pd intermetallic compound by the iodine addition. For the reactor with the superhydrophobic Pt–Pd/Al2O3 catalyst coating, under the conditions simulating the nuclear accident, the reaction was ignited immediately as soon as the hydrogen was introduced at 298 K and the hydrogen conversion kept 100% when the reaction temperature exceeded 398 K. The superhydrophobic Pt–Pd/Al2O3 catalyst coating showed great potential for the mitigation of hydrogen containing various poisons during the nuclear accident.