Abstract This article proposes a novel application combining the thermal catalytic oxidation with solar-collected wall (SWTCO) in buildings without auxiliary energy. Thermal catalyst MnO x -CeO 2 was prepared by the method of modified coprecipitation. The performance and kinetics of MnO x -CeO 2 for catalytic oxidation of indoor formaldehyde were investigated. Once-through experiments at different concentrations of 300–4300 ppb and temperatures 20–100 °C were conducted. Moreover, formaldehyde conversion experiments in SWTCO system at several typical indoor concentrations (289 ppb, 587 ppb and 1374 ppb) were performed. Furthermore, a simple system model predicting the degradation of indoor formaldehyde versus the time in SWTCO system was built. Results were as follows: (1) The reaction rate expression considering two parameters i.e. concentration and temperature based on modified L-H model fit the experimental data well; (2) System model calculation results showed initial formaldehyde concentration was an important factor to the formaldehyde degradation capability; (3) SWTCO system could realize high pollutant-removal efficiency and low energy costs simultaneously under higher temperature compared with the system using electrical heating; (4) The purification time constant increased with the horizontal solar radiation and the influence of concentration in typical indoor formaldehyde concentration on it could be neglected.