1 23 Journal of Materials Science: Materials in Electronics ISSN 0957-4522 Volume 27 Number 3 J Mater Sci: Mater Electron (2016) 27:2994-3002 DOI 10.1007/s10854-015-4121-x Influence of gadolinium precursor on the enhanced red shift of Gd/SnO 2 –TiO 2 nanoparticles and catalytic activity Muhammad Akhyar Farrukh, Maryam Shahid, Iqra Muneer, Shaghraf Javaid & Muhammad Khaleeq-ur-Rahman