Photo-stimulated proton-coupled electron transfer in quasi-amorphous WO₃and MoO₃thin films

Nanosized WO3 thin film as a multifunctional hydrogen material for achieving photolysis in CuCl films via hydrogen photosensitization

“…The atomic force microscope investigations showed that the WO 3 films deposited onto unheated substrates were be nanocomposites [9,11], whereas the absence of long-range order was confirmed by X-ray analyses. For this reason, the films can be characterized as ''quasi-amorphous''.…”

“…The surface is essentially heterogeneous with exceptionally high chemical reactivity for some surface centres [9,11]. These films have $ 0.8 of WO 3 bulk density [1].…”

“…First WO 3 can play the role of a catalyst in photoinduced hydrogen transfer, if specially selected organic molecules (hydrogen donors) are adsorbed on the WO 3 film surface; hydrogen atoms being detached from the adsorbed molecules as the result of excitation of the WO 3 film surface by photons with the energy exceeding the oxide forbidden energy gap and transfer of surface excitation to the adsorbed molecules [6][7][8][9][10].…”

“…Very often, methanol is used as a hydrogen donor, like in this study, and for the one of the photogenerated holes, according to [9,10], it is possible to write h + + (CH 3 OH) ads -H + +( _ CH 2 OH) ads (2) The hydrogen transfer between the donor molecule and the oxide surface yielded a scavenge of the hole and formation of a _ CH 2 OH radical, which in fact is an exchange of the photogenerated hole for a proton. This in turn makes the life-time of an electron, photogenerated together with the hole, indefinitely long, since scavenging of the hole makes recombination impossible.…”

Oxide‐Based Electrochromics

“…Considering WO 3 , there has been detailed work recently to investigate photostimulated hydrogen atom transfer quantum reactions [66] consistent with resonant tunneling [67]; this work elucidates the theoretical underpinning for understanding the interplay of photochromism and electrochromism in WO 3 and similar oxides. Figure 13.7 shows data on insertion/extraction of charge in a 240 cm 2 EC foil-type device for visor applications in the dark and subjected to weak UV irradiation due to exposure to an overcast sky at an ambient temperature of 15 C. Charging at À1.6 V was performed over 1 min; the device was then rested for 1 min, and discharge took place at 1.4 V for 1 min.…”