Ag-Ni and Al-Ni Nanoparticles for Resistive Response of Humidity and Photocatalytic Degradation of Methyl Orange dye

Abstract In the present work, Ag-Ni and Al-Ni nanoparticles (NPs) were synthesized via co-precipitation method and their structural, resistive response of humidity and photocatalytic degradation properties evaluated. The as prepared NPs were characterized by XRD, FTIR, TGA, DRS, BET, XPS, SEM and TEM. XRD patterns indicated well defined peaks for Ag, Al and Ni elements. SEM and TEM micrographs displayed nano size heterogeneous microstructures both for Ag-Ni and Al-Ni NPs along with some agglomeration. The average particle size calculated by XRD, SEM and TEM was ranged from 42-95 nm. FTIR and XPS investigated about various functional groups and elemental contents within the synthesized samples. TGA showed total weight loss of 14.93 and 39.29% whereas, surface area, pore volume and pore size were 18.63m2/g, 0.2846 mL/g, 1.3277 nm and 8.52 m2/g, 0.0556 mL/g, 1.3678 nm for Ag-Ni and Al-Ni NPs respectively. Low band gap energies ∼1.30 (for Ag-Ni) and 1.51eV (for Al-Ni) were calculated via DRS. Resistance was decreased from (879 to 240MΩ for Ag-Ni and 745 to 169MΩ for Al-Ni NPs) with increased humidity level (from 10 to 95%) due to surface adsorption of water by fabricated samples. Response time ∼60s, 59s and recovery time ∼39s, 20s with low hysteresis was measured for Ag-Ni and Al-Ni NPs respectively. Furthermore, photocatalytic degradation ability of the synthesized samples was also investigated against Methyl Orange (MO) dye. Ag-Ni and Al-Ni NPs showed 91 and 75% degradation during total time of 80 and 120 minutes respectively. Degradation ability of the samples was also evaluated for various factors such as catalyst loading, pH and different scavengers. Fast response/recovery time, low hysteresis, better catalysis and excellent stability indicated for both the samples categorize them well suited for resistive humidity sensing and photocatalytic degradation of MO dye from industrial effluents.