In Thailand, the main fuels for electricity generation are natural gas and coal (70% and 20% consumption, respectively). The unpurified natural gas contains the impurities toxic gas i.e. hydrogen sulfide (H₂S). For coal, it also contains H₂S via the coal gasification processes. Therefore, the removal of H₂S from the natural gas and synthetic gas from coal is an important process for the fuel gas prior to the further utilization in vehicle and engine. Zinc oxide and zinc-based sorbents are very attractive for the H₂S removal due to their high equilibrium constant for sulfidation and thermal stability of sorbents. In this research work, zinc oxide (ZnO) and 3 types of metal doped-zinc oxide sorbents were synthesized and characterized. These 4 sorbents were prepared by incipient wetness impregnation method on alumina support (Al₂O₃) and then were heated from 30 °C to 500 °C under air flow by using multi-step of calcination. The transition metals that were added on ZnO sorbents were copper (Cu²⁺), manganese (Mn²⁺), and gadolinium (Gd³⁺). The effect of transition metal doped on zinc oxide sorbent on the surface area and pore volume of the sorbent was studied by using N₂ adsorption and desorption. In addition, physical and chemical properties of these 4 sorbents were measured by X-ray fluorescence technique and thermal gravimetric analysis. Results from X-ray fluorescence measurement of the synthesized copper doped-zinc oxide sorbents confirm the weight ratio of zinc per copper as 19:1. The synthesized ZnO and metal doped-zinc oxide sorbents have high total pore volume of pores (approximately 0.4 cm³/g) and have average pore width around 10 nm which is suitable for the adsorption of small molecule of gas (i.e. H₂S).