ZnGa_2−xAl_xO₄ (x = 0 ≤ 2) spinel for persistent light emission and HER/OER bi-functional catalysis

Abstract

The unique PL and afterglow properties show the potential of ZnGa2O4 for energy and solid-state lighting applications. Solid solution of ZnGa2O4 and ZnAl2O4 showed promise as an efficient bifunctional electrocatalyst for both HER and OER.

Improved catalytic activity on transitioning from inverse to normal spinel in Zn2−xGa2xSn1−xO4: a robust bifunctional OER and HER electrocatalyst

“…The blue emission is mainly due to the self-activation of the GaO 6 unit whereas the green emission is due to the presence of oxygen vacancies which are observed in our earlier work also. 34 With increase in the Sn content a shift in the emission profile is observed, which is also clearly visible from the Commission Internationale de I'Eclairage (CIE) chromaticity diagram. On going from the inverse spinel (Zn 2 SnO 4 ) to the spinel (ZnGa 2 O 4 ) structure the color changes from orange to blue which can be utilised as a color tunable phosphor.…”

“…The peak at 670 cm −1 is a second order mode. 34,36 Additionally, Zn 2 SnO 4 also depicted five Raman active modes present at 223, 375, 525 and 662 cm −1 according to group theory. The Raman peak at 525 cm −1 corresponded to the internal vibration of the oxygen tetrahedron, whereas the peak at 662 cm −1 represents the stretching vibration of short M–O in the MO 6 octahedron.…”

“…2b, the core level spectrum of Zn confirmed its presence in the +2 oxidation state, having two characteristic peaks of Zn 2p at 1021.7 (Zn 2p 3/2 ) and 1044.7 eV (Zn 2p 1/2 ) with a spin–orbit splitting value of 23 eV. 34 The core level spectrum of Ga 3d (Fig. 2c) depicted a single peak at 19.3 eV corresponding to the trivalent gallium (Ga 3+ ).…”

“…In the case of ZnGa 2 O 4 two bands were observed at 488 and 590 cm −1 which corresponded to the vibration of Zn–O and Ga–O–Zn bonds. 34 For Zn 2 SnO 4 , the FT-IR spectrum consisted of a broad peak at 575 cm −1 depicting the vibration of the Sn–O–Zn bond and the shoulder peak at 650 cm −1 corresponded to the vibration of the Sn–O bond. 35 Similarly, the intermediate compositions exhibited broad spectral features confirming their successful synthesis Fig.…”

Strategic Ni-doping improved electrocatalytic H2 production by Bi3O4Br in alkaline water

“…Over the last few decades, extensive research efforts have been made to develop an electrocatalyst that can produce hydrogen via the electrocatalytic splitting of water at a lower overpotential with appreciable rates. [5][6][7][8][9] Electrocatalytic water splitting can be carried out in both acidic and alkaline media, the lack of acid-tolerant counter electrode material is a bottleneck for the production of multimillion tons of H 2 via acidic electrolyzers. [10][11][12] Therefore, a major emphasis has been given to the quest for a stable and highly active catalyst for alkaline HER in the past few decades.…”