Synergistic effect of doping and defect in achieving white light emission and oxygen reduction catalysis in Ce1-xSmxPO4

Abstract

Multifunctional materials owing to their efficacy to perform more than one job have attracted the attention of global materials science community to resolve the issue of material crunch and reduce the work load. Here, in this work, we have demonstrated the suitability of CePO4:Sm3+ (CPOS) phosphor for white light luminophore and oxygen reduction catalyst. Raman spectroscopy confirmed the stabilization of monoclinic phase for CPOS. White light emission with correlated color temperature (CCT) favoring cool white feature in CPOS is endowed by inefficient host to dopant energy transfer (HDET). X-ray photoelectron spectroscopy (XPS) suggested presence of both Ce3+ and Ce4+ in CPOS with later in lower fraction. XPS results also showed the presence of surface oxygen in CPOS which along with mixed oxidation state of cerium on the surface may be aiding CPOS to work as electrocatalysts for oxygen reduction reaction (ORR). The best electrocatalytic performance was achieved with 1.0% Sm doped sample which has higher concentration of oxygen associated with Ce (IV) on the surface.