LaTaON₂ Mesoporous Single Crystals for Efficient Photocatalytic Water Oxidation and Z-Scheme Overall Water Splitting

Abstract

LaTaON2 porous single crystals (PSCs), integrating structural coherence and porous microstructures, will warrant promising photocatalytic performance. The absence of grain boundaries in PSCs ensures rapid photocarrier transportation from bulk to the surface, thereby mitigating photocarriers’ recombination. Porous microstructures not only provide ample reachable surface to host photochemical reactions but also reinforce photon-matter interactions by additional photon reflection/scattering. Here, we have synthesized LaTaON2 PSCs via a topotactic route and show significantly improved photocatalytic performance. Efficient water oxidation into O2 has been realized by LaTaON2 PSCs with an apparent quantum efficiency as high as 5.7% at 420 ± 20 nm. Stable overall water splitting into stoichiometric H2 and O2 has also been achieved in a Z-scheme setup using LaTaON2 PSCs as the O2 evolution photocatalyst. These results not only prove that PSCs facilitate photocarrier migrations, which in turn deliver exceptional photocatalytic performance, but also imply that PSCs are useful to reinvigorate conventional semiconductor photocatalysts toward efficient solar energy conversions.

Boosting visible-light-driven water splitting over LaTaON2via Al doping

“…The fitted parameters, such as BEs and FWHMs, are tabulated in Table S5. Apparently, the surface of the pristine LaTaON 2 (x = 0.00) contains abundent Ta 4+ defects, which may trap charges, leading to severe charge recombination [19,21]. It is noteworthy that Ta 4+ defects are considerably reduced after introducing Al to LaTaON 2 as can be seen from the change of peak area ratio for Ta 4+ /Ta 5+ species (Tables S5 and S6, and Fig.…”

“…H 2 liberation from water by solar-driven photocatalysis provides a promising means to address the above concerns due to its simplicity, scalability, and environmental friendliness [6][7][8][9][10][11][12][13][14][15]. Notwithstanding these appealing prospects, practical application of photocatalytic techniques awaits fundamental advancements on photocatalytic materials in terms of light harvest, separation, and transfer of photocarriers (electrons and holes) [16][17][18][19][20][21]. In particular, narrow bandgap semiconductors that are active for water splitting reactions are strongly desired [8,12,13,15,[18][19][20][21].…”

“…Notwithstanding these appealing prospects, practical application of photocatalytic techniques awaits fundamental advancements on photocatalytic materials in terms of light harvest, separation, and transfer of photocarriers (electrons and holes) [16][17][18][19][20][21]. In particular, narrow bandgap semiconductors that are active for water splitting reactions are strongly desired [8,12,13,15,[18][19][20][21].…”

“…Perovskite-type oxynitrides have drawn increasing attention as promising water splitting photocatalysts [14,[19][20][21][22][23][24][25][26][27][28]. This has been ascribed to their stronger visible light absorption as well as proper band edge alignments that are thermodynamically feasible for water redox reactions [29][30][31][32][33][34][35][36].…”

A Dual‐Channel Charge Transfer Heterostructure toward Boosting Photocatalytic Hydrogen Evolution

“…A series of promising photocatalysts have been designed and constructed, such as metal sulfides, metal nitrides, conjugated polymers, and so on. [4][5][6][7][8][9][10][11] These photocatalysts achieved stirring progress for photocatalytic H 2 evolution. However, their catalytic activity is seriously suppressed by the sluggish photo-generated carrier transfer and insufficient (buried) active sites.…”