The water oxidation half-reaction is considered to be a bottleneck for achieving highly efficient solar-driven water splitting due to its multiproton-coupled four-electron process and sluggish kinetics. Herein, a triadic photoanode consisting of dual-sized CdTe quantum dots (QDs), Co-based layered double hydroxide (LDH) nanosheets, and BiVO4 particles, that is, QD@LDH@BiVO4, was designed. Two sets of consecutive Type-II band alignments were constructed to improve photogenerated electron-hole separation in the triadic structure. The efficient charge separation resulted in a 2-fold enhancement of the photocurrent of the QD@LDH@BiVO4 photoanode. A significantly enhanced oxidation efficiency reaching above 90% in the low bias region (i.e., E < 0.8 V vs RHE) could be critical in determining the overall performance of a complete photoelectrochemical cell. The faradaic efficiency for water oxidation was almost 90%. The conduction band energy of QDs is ∼1.0 V more negative than that of LDH, favorable for the electron injection to LDH and enabling a more efficient hole separation. The enhanced photon-to-current conversion efficiency and improved water oxidation efficiency of the triadic structure may result from the non-negligible contribution of hot electrons or holes generated in QDs. Such a band-matching and multidimensional triadic architecture could be a promising strategy for achieving high-efficiency photoanodes by sufficiently utilizing and maximizing the functionalities of QDs.

The rational design of advanced structures consisting of multiple components with excellent electrochemical capacitive properties is one of the crucial hindrances to be overcome for high‐performance supercapacitors (SCs). Herein, a superfast and facile synthesis of flower‐like NiMn‐layered double hydroxides (NiMn‐LDH) with high SC performance using an electrodeposition process on nickel foam is proposed. Oxygen vacancies are then modulated via mild H2O2 treatment for the first time, significantly promoting the electrochemical energy storage performance. The oxygen‐vacancy abundant NiMn‐LDH (Ov‐LDH) reaches a maximum specific capacity of 1183 C g−1 at the current density of 1 A g−1 and retains a high capacity retention of 835 C g−1 even at a current density of up to 10 A g−1. Furthermore, the assembled asymmetric SC device achieves a high specific energy density of 46.7 Wh kg−1 at a power density of 1.7 kW kg−1. Oxygen vacancies are proven to play a vital role in the improvement of electrochemistry performance of LDH based on experimental and theoretical studies. This vacancy engineering strategy provides a new insight into SC active materials and should be beneficial for the design of the next generation of energy storage devices.

In the past few years, attention has been focused on the research field of one-dimensional nanostructural materials, both because of their fundamental importance and because of the wide range of potential applications in nanodevices.[1±12] Many attempts have been made to fabricate onedimensional nanostructure materials utilizing a variety of nanofabrication techniques and crystal growth methods. [1,5,6,13±20] However, it is still a challenge to synthesize an aligned and well-distributed single-crystal nanowire array. Electrochemical synthesis using a template is one of the most efficient methods for the growth of nanowires because the growth occurs almost exclusively in the direction normal to the substrate surface. [20] In addition, anodic aluminum oxide possesses uniform and nearly parallel porous structures; hence they have been used as an ideal template to produce cylindrical nanowires with a narrow diameter distribution. As CdS is one of the most important II±VI group semiconductors, having vital applications in solar cells and optoelectronic and electronic devices, the AC electrodeposition of CdS nanowires in porous anodic aluminum oxide (AAO) templates has been investigated.[21±23]However, structural studies have demonstrated that large numbers of stacking faults and twinned segments are present in these nanowires. [23] Recently, an aligned CdS singlecrystal nanowire array has been produced using DC electrolysis in AAO templates from a dimethylsulfoxide (DMSO) solution containing cadmium chloride and elemental sulfur.[24] Here we report a new electrochemical process to prepare CdS single-crystal nanowires using electrochemically induced deposition [25] in the pores of an AAO template from an acidic chemical bath containing cadmium chloride and thioacetamide (TAA). The details of the growth of the AAO templates, the deposition of the CdS, and the characterization of the nanowires can be found in the Experimental section. Figure 1a shows a typical transmission electron microscopy (TEM) image of CdS nanowires prepared by electrochemically induced deposition in the AAO template with pore diameters of about 90 nm. It can be seen that the diameter of the nanowires is about 90 nm, which corresponds to the diameter of the pores of the template used. The lengths of the nanowires range from 3 to 5 mm after deposition for 8 h. Figure 1b shows a TEM image of the nanowires deposited in the template with pore diameters of about 20 nm; the uniform diameters of about 20 nm and smooth surfaces are clearly visible. After deposition for 8 h, the length of the nanowire is up to 10 mm, which is 2±3 times as long as the nanowires deposited in a template with pore diameters of 90 nm under the same deposition conditions. This experimental result indicates that the growth rate of the nanowire increases with decreasing pore size of the AAO template.The chemical composition of the nanowires was determined using X-ray energy dispersion analysis (EDAX) and Raman spectroscopy. The EDAX spectrum shown in Figure 2a reveals that the nano...

Transition‐metal phosphides have flourished as promising candidates for oxygen evolution reaction (OER) electrocatalysts. Herein, it is demonstrated that the electrocatalytic OER performance of CoP can be greatly improved by constructing a hybrid CoP/TiOx heterostructure. The CoP/TiOx heterostructure is fabricated using metal–organic framework nanocrystals as templates, which leads to unique hollow structures and uniformly distributed CoP nanoparticles on TiOx. The strong interactions between CoP and TiOx in the CoP/TiOx heterostructure and the conductive nature of TiOx with Ti3+ sites endow the CoP–TiOx hybrid material with high OER activity comparable to the state‐of‐the‐art IrO2 or RuO2 OER electrocatalysts. In combination with theoretical calculations, this work reveals that the formation of CoP/TiOx heterostructure can generate a pathway for facile electron transport and optimize the water adsorption energy, thus promoting the OER electrocatalysis.