Novel mesoporous ZnxCd1−xS nanoparticles as highly efficient photocatalysts

Abstract Porous semiconductor photocatalysts which are active under illumination by visible light have attracted extensive attention recently due to their remarkable well-designed physical and chemical properties. Here, novel mesoporous Zn x Cd 1− x S nanoparticles have been successfully fabricated by a two-steps strategy: Al-Zn x Cd 1− x S nanoparticles which are homogeneously distributed within the confinement of an amorphous alumina matrix was first synthesized by in situ gas–solid reaction of a single precursor—a Zn 2+ ,Cd 2+ ,Al 3+ -containing layered double hydroxides (ZnCdAl-LDHs)—with gaseous H 2 S; subsequently, selective leaching of amorphous alumina by sodium hydroxide solution from the as-prepared Al-Zn x Cd 1− x S nanoparticles was carried out, with the aim of achieving the introduction of mesopority in the chalcogenide semiconductor. The resulting mesoporous Zn x Cd 1− x S nanoparticles can retain the uniform distributed structure with a network-like manner after the selective leaching of amorphous alumina. The absorption edge of the mesoporous Zn x Cd 1− x S exhibit a monotonic blue shift within the visible light region as the amount of residual alumina decreased. The photocatalytic activities of the mesoporous Zn x Cd 1− x S samples for the photodegradation of methylene blue (MB) dye molecules increase with the decline of alumina. And, the mesoporous Zn x Cd 1− x S exhibits an enhanced photocatalytic performance compared to the pure CdS sample obtained from the same procedure without Zn 2+ , the unleached Al-Zn x Cd 1− x S sample and the sample obtained by a coprecipitation method with the same composition. The homogeneous structure of the mesoporous Zn x Cd 1− x S and the abundant surface hydroxyl groups are proposed to be beneficial to the generation of hydroxyl radicals, identified by electron spin resonance (ESR) spectra, leading to the higher photocatalytic activity.