Electroless platinum and palladium deposition over alumina coated stainless steel plates and their catalytic activity for hydrogen mitigation in severe nuclear accidents

Abstract

This work focused on platinum and palladium-based autocatalytic plates, which used to remove hydrogen. The six sandblasted stainless steel plates were coated with platinum and palladium metals using the electroless coating method. The three plates A-01, A-02, A-03 were first coated with alumina using the sol-gel dip method, and after that, different ratios of platinum and palladium were deposited on them. The three other plates, B-01, B-02, B-03 (without alumina coated), were coated directly with different ratios of platinum and palladium. The platinum and palladium ratio used for coating these plates were Pt 80%: Pd 20%; Pt 90%: Pd 10%, and Pt 70%: Pd 30. The coating of these plates was characterized using Scanning Electron Microscopy, X-rays Fluorescence Spectroscopy, and their catalytic efficiency was measured by the Passive Autocatalytic Recombiner testing rig method. It was found that the plates coated with alumina using two dipping cycles are suitable for different coating of mixed metals by electroless coating method compared to three dipping cycles. It was observed that the alumina-coated catalytic plates (A-01, A-02, A-03) exhibited excellent catalytic efficiency as compared to those without alumina-coated plates (B-01, B-02, B-03). Furthermore, the catalytic efficiency of A-03 and B-03 is higher than other plates. It was also found that the catalytic efficiency of A-03 is higher than B-03. The best coating ratio is Pt 90%: Pd10%, and alumina-coated plates give excellent results.