Study of the applicability of ACdSe (A – Co, Ni) thin films as catalysts for heavy metal capture

Abstract

Expansion of the possibilities of using photoactive thin films with a unique combination of optical and morphological characteristics as a basis for creation of highly efficient catalysts for the aqueous media purification is one of the promising research areas in modern materials science, which has both fundamental significance and potential for practical application. This study examines the prospects for using modified thin CdSe films by substituting nickel or cobalt for cadmium and selenium as a basis for creating highly efficient catalysts for the aqueous media purification from heavy metals such as arsenic, manganese and iron. A rather inexpensive electrochemical synthesis method was proposed as a method for obtaining thin films, in which the substitution effect is achieved by addition of nickel or cobalt sulfates to the electrolyte, which allows obtaining films with an equally probable distribution of elements in the composition of the synthesized films. Optical spectroscopy methods were used as methods for characterization of the initial samples, which made it possible to establish the dependences of the change in the band gap and absorption bands on the composition of the synthesized films, as well as to anticipate the influence of morphological features on optical absorption. During the conducted studies it was established that partial substitution of nickel and cobalt for cadmium and selenium in the composition of films results in growth in the adsorption efficiency of heavy metals, alongside operation stability maintenance of modified films during cyclic tests. At the same time, enhancement of the adsorption efficiency of heavy metals for modified films is due to both an alteration in the optical properties of the films and morphological features associated with the specific surface area growth due to a reduction in the grain size and a more developed surface.