The introduction of oxygen vacancies (Ov) has been regarded as an effective method to enhance the catalytic performance of photoanodes in oxygen evolution reaction (OER). However,t heir stability under highly oxidizing environment is questionable but was rarely studied. Herein, NiFe-metal-organic framework (NiFe-MOFs) was conformally coated on oxygen-vacancy-richB iVO 4 (Ov-BiVO 4 )a st he protective layer and cocatalyst, forming ac ore-shell structure with caffeic acid as bridging agent. The as-synthesized Ov-BiVO 4 @NiFe-MOFs exhibits enhanced stability and aremarkable photocurrent density of 5.3 AE 0.15 mA cm À2 at 1.23 V( vs. RHE). The reduced coordination number of Ni(Fe)-O and elevated valence state of Ni(Fe) in NiFe-MOFs layer greatly bolster OER, and the shifting of oxygen evolution sites from Ov-BiVO 4 to NiFe-MOFs promotes Ov stabilization. Ovs can be effectively preserved by the coating of at hin NiFe-MOFs layer,l eading to ap hotoanode of enhanced photocurrent and stability.

Photoelectrochemical (PEC) water splitting into hydrogen and oxygen is a promising solution for the conversion and storage of solar energy. Because sluggish water oxidation is the bottleneck of water splitting, the design and preparation of an efficient photoanode is intensively investigated. Currently, all known photoanode materials suffer from at least one of the following drawbacks: ① low carriers separation efficiency; ② sluggish surface water oxidation reaction; ③ poor long‐term stability; ④ insufficient water adsorption and gas desorption. Core–shell configurations can endow a photoanode with improved activity and stability by coating an overlayer that plays energetic, catalytic, and/or protective roles. The construction strategy has an important effect on the activity of a core–shell photoanode. Nonetheless, the mechanism for the improvement of performance is still ambiguous and is worthy of a closer examination. In this review, the successes and challenges of core–shell photoanodes for water oxidation, focusing on synthesis strategies as well as functionalities (facilitating carrier separation, surface reaction promotion, corrosion prevention, and bubble detachment) are explored. Finally, the perspectives of this class of materials in terms of new opportunities and efforts are discussed.

No abstract

The photoelectrocatalytic (PEC) oxidation of glycerol into highly value-added products is attractive, but it is extremely challenging to limit the oxidation products to the valuable C3 chemicals. The hole concentration and surface atomic arrangement of a photoanode can be modulated by controlling facet exposure, thus tuning the activity and selectivity. Herein, we report for the first time the formation of a WO3 photoanode with predominant exposure of {202} facets by a secondary hydrothermal method. The photoanode exhibits superior PEC glycerol conversion efficiency, giving an 80% selectivity to glyceraldehyde with a production rate of 462 mmol h–1 m–2. Also, the faraday efficiency for the C3 product reaches 98.6%. We made comparison between the {202} facets and the commonly studied {200} facets using experimental and theoretical methods. It is disclosed that the former enhances not only the adsorption and activation of glycerol via the terminal hydroxyl groups but also the desorption of glyceraldehyde.

No abstract