This study investigates the role of lattice oxygen in hydrogen sensing reactions, revealing that lattice oxygen contributes to the sensing process, contrary to the traditional belief that only surface-adsorbed oxygen is involved. Using in-situ characterization techniques and density functional theory (DFT) calculations, the research demonstrates that lattice oxygen plays a crucial role in hydrogen sensing. The p-band center of oxygen is identified as a key factor in regulating the participation of lattice oxygen in gas-sensing reactions. The study focuses on germanium-doped tin dioxide (SGO) as a case study, showing that SGO exhibits high response values, good selectivity, and fast response times. The results indicate that lattice oxygen is more easily involved in the sensing process, leading to enhanced performance. The study also highlights the importance of understanding the sensing mechanism for the development of high-performance gas-sensing materials. The findings suggest that the lattice oxygen participation mechanism is a fundamental mechanism that differs from the conventional chemisorbed oxygen mechanism. The research provides insights into the dynamic evolution of the gas-sensing reaction and the role of lattice oxygen in hydrogen sensing. The study concludes that lattice oxygen is actively involved in the hydrogen sensing reaction, contributing to the enhanced performance of the material. The results have implications for the design of hydrogen-sensing materials and the understanding of gas-sensing mechanisms.This study investigates the role of lattice oxygen in hydrogen sensing reactions, revealing that lattice oxygen contributes to the sensing process, contrary to the traditional belief that only surface-adsorbed oxygen is involved. Using in-situ characterization techniques and density functional theory (DFT) calculations, the research demonstrates that lattice oxygen plays a crucial role in hydrogen sensing. The p-band center of oxygen is identified as a key factor in regulating the participation of lattice oxygen in gas-sensing reactions. The study focuses on germanium-doped tin dioxide (SGO) as a case study, showing that SGO exhibits high response values, good selectivity, and fast response times. The results indicate that lattice oxygen is more easily involved in the sensing process, leading to enhanced performance. The study also highlights the importance of understanding the sensing mechanism for the development of high-performance gas-sensing materials. The findings suggest that the lattice oxygen participation mechanism is a fundamental mechanism that differs from the conventional chemisorbed oxygen mechanism. The research provides insights into the dynamic evolution of the gas-sensing reaction and the role of lattice oxygen in hydrogen sensing. The study concludes that lattice oxygen is actively involved in the hydrogen sensing reaction, contributing to the enhanced performance of the material. The results have implications for the design of hydrogen-sensing materials and the understanding of gas-sensing mechanisms.