The selectivity of hydrocarbon oxidation on metal surfaces is influenced by various reaction conditions, including temperature, pressure, and gas composition. These factors can affect the reaction pathways, intermediates, and the overall rate of the reaction, ultimately impacting the selectivity of the desired product.1. Temperature: The temperature of the reaction plays a crucial role in determining the selectivity of hydrocarbon oxidation on metal surfaces. At lower temperatures, the reaction is generally slower and may favor the formation of specific intermediates or products. As the temperature increases, the reaction rate increases, and the energy barriers for various reaction pathways may be overcome, leading to the formation of different products. Higher temperatures can also lead to the desorption of adsorbed species from the metal surface, which can affect the selectivity.2. Pressure: The pressure of the reaction system can also influence the selectivity of hydrocarbon oxidation on metal surfaces. Higher pressures can lead to an increased concentration of reactants and intermediates on the metal surface, which can affect the reaction pathways and selectivity. Additionally, higher pressures can promote the formation of specific products by stabilizing certain reaction intermediates or by influencing the adsorption/desorption equilibrium of the reactants and products on the metal surface.3. Gas composition: The composition of the gas phase in the reaction system can significantly impact the selectivity of hydrocarbon oxidation on metal surfaces. The presence of different reactants, such as oxygen, can affect the reaction pathways and the formation of specific intermediates. Additionally, the presence of other gases, such as water vapor or inert gases, can influence the adsorption/desorption equilibrium of the reactants and products on the metal surface, thereby affecting the selectivity.In summary, the selectivity of hydrocarbon oxidation on metal surfaces is influenced by various reaction conditions, including temperature, pressure, and gas composition. By carefully controlling these factors, it is possible to optimize the selectivity of the desired product in hydrocarbon oxidation reactions.