Enriched oxygen vacancies of copper(I) oxide particles for enhanced removal of hydrogen sulfide at room temperature

In this work, the removal of hydrogen sulfide (H2S) by copper(I) oxide (Cu2O) and copper(II) oxide (CuO) particles synthesized by thermal decomposition (TD) and liquid reduction is investigated in a fixed-bed experiment at 25 °C and 1 atm. The surface oxygen vacancies (VOs) contents of the prepared Cu2O samples are more than twice that of the synthesized CuO particles, which are closely related to H2S removal performance. The H2S adsorption capacity of Cu2O prepared is 135.6 mg g−1, approximately 27 times that of CuO. A dense CuS layer formed on the CuO surface makes it significantly less reactive with H2S than Cu2O. Due to the crystal structure and abundant VOs on the Cu2O surface, the weak Cu–O bonds are broken during the sulfurization process, causing the rupture of the surface layer. And the sulfidation reaction gradually extends to the interior through the cracked surface layer, leading to the excellent sulfurization performance of Cu2O. The larger H2S adsorption capacity of Cu2O prepared by TD than that of Cu2O prepared by liquid reduction could be attributed to the presence of more numbers of VOs and Cu atoms on the surface. Moreover, H2O can enter VOs and promote the dissociation of H2S into S2−, thereby improving H2S adsorption capacity. This work demonstrates that Cu2O is a promising sorbent for H2S removal at room temperature.