Investigation on the Structure–Function Relationship of Atomic-Layer-Deposited Platinum Additives on Tungsten Trioxide Gas Sensor Materials

Different Pt structures were deposited on WO3 by using atomic layer deposition. The gas sensing properties, structures of the Pt loadings, and their influence on the gas detection mechanism were investigated using extensive material characterization and operando spectroscopies. The results show that, depending on the number of atomic layer deposition cycles, different Pt structures can be obtained, which influence the gas detection in different ways. The found structures range from predominantly ionic Pt sites over oxidic particles to partially oxidized metallic particles. It was found that single ion sites and small oxidic particles have the most effective influence on gas detection, whereas partially oxidized metal particles lead to a lower gas sensing performance.