Light energy storage and photoelectrochemical behavior of the titanate nanotube array/Ni(OH)2 electrode

Energy Storage in Bifunctional TiO2 Composite Materials under UV and Visible Light

“…It appears that the TiO 2 /Ni(OH) 2 bilayer film can potentially be used as a photochromic material. Figure 14 [33] shows the similar color changes of the TiO 2 /Ni(OH) 2 electrode upon irradiation. Before the irradiation, the color was gray.…”

Enhanced energy storage of a UV-irradiated three-dimensional nanostructured TiO2–Ni(OH)2 composite film and its electrochemical discharge in the dark

“…Note that the composite film electrode exhibits the largest discharge capacity of 11.54 mC cm À2 at the 13th cycle. Compared to those TiO 2 -Ni(OH) 2 film electrodes in previous reports [32][33][34][35][36], the as-prepared 3D nanoporous composite film electrode displays notably enhanced discharge performance at a much higher current density.…”

“…The IPCE value is calculated to be 10.6%. It is obvious that the present system shows a much higher IPCE than the previous systems at open-circuit states [32][33][34][35][36], moreover this value is also significantly larger than that (6.8%) of the coupling system in our previous work [37]. Even for the UV-induced reductive energy storage, the maximal apparent quantum yield of the optimum WO 3 -TiO 2 system was reported to be $8% [22], lower than the corresponding value for the oxidative energy storage in the present investigation.…”

“…Reductive energy (photogenerated electrons from a UV-irradiated TiO 2 ) may be stored in some redox-active n-type semiconductors such as WO 3 [27][28][29], MoO 3 [30] or H 3 PW 12 O 40 (PWA) [31], and the stored energy can give rise to anticorrosion [27] or bactericidal effects [29] after dark. On the other hand, oxidative energy (photogenerated holes from TiO 2 ) can be stored in a redox-active p-type semiconductor, Ni(OH) 2 [32][33][34][35][36]. The stored oxidative energy may be used for electrochemical discharge, removal of toxic compounds and photochromic devices.…”

“…Although some investigations on UV-induced oxidative energy storage have been undertaken [32][33][34][35][36], the maximal apparent quantum yield of the TiO 2 -Ni(OH) 2 electrode systems at opencircuit states is reported to be 0.12%, much smaller than that ($8%) of the optimum WO 3 -TiO 2 composite system for reductive energy storage [22]. For the TiO 2 -Ni(OH) 2 composite film systems UV-irradiated at open-circuit state, the hole-electron recombination and the reduction of NiOOH by photogenerated electrons and reductive reaction products (e.g., H 2 O 2 ) are responsible for their low oxidative energy storage efficiency [32,36].…”