Activated carbon (AC) supported manganese oxide sorbents were prepared by the supercritical water impregnation (SCWI) using two different precursor of Mn(NO3)(2) (SCW(N)) and Mn(Ac)(2)center dot 4H(2)O (SCW(A)). Their capacities of removing H2S from coal gas were evaluated and compared to the sorbents prepared by the pore volume impregnation (PVI) method. The structure and composition of different sorbents were characterized by XRD, SEM, TEM, XPS and XANES techniques. It is found that the precursor of active component plays the crucial role and SCW(N) sorbents show much better sulfidation performance than the SCW(A) sorbents. This is because the Mn3O4 active phase of the SCW(N) sorbents are well dispersed on the AC support, while the Mn2SiO4-like species in the SCW(A) sorbent can be formed and seriously aggregated. The SON(N) sorbents with 2.80% and 5.60% manganese are favorable for the sulfidation reaction, since the Mn species are better dispersed on the SCW(N) sorbents than those on the PV(N) sorbents and results in the better sulfidation performance of the SON(N) sorbents. As the Mn content increases to 11.20%, the metal oxide particles on AC supports aggregate seriously, which leads to poorer sulfidation performance of the SCW(N)11.20% sorbents than that of the PV(N)11.20% sorbents. (C) 2012 Elsevier B.V. All rights reserved.