Semiconductor-based photocatalytic technology for CO 2 reduction to produce fuels is a key toward developing new sustainable energy sources, but this technology remains a huge challenge. Herein, a p−n heterojunction photocatalyst composed of Co-doped TiO 2 nanobelts (Co−TiO 2 NBs) coupled with Co 3 O 4 nanoparticles (NPs) is designed through a two-step operation of hydrothermal ion exchange and medium temperature calcination. Characterization of the product demonstrates that Co 3 O 4 NPs are intimately embedded on the surface of Co−TiO 2 NBs, and they provide an ideal heterointerface with strong electron interaction. As compared to the single-phase TiO 2 NBs and Co 3 O 4 NPs, the Co 3 O 4 /Co−TiO 2 nanocomposite exhibits significantly improved photocatalytic performance for the conversion of CO 2 to H 2 O under simulated solar irradiation. It is shown that the p− n junctions constructed by p-type Co 3 O 4 NPs and n-type Co−TiO 2 NBs can effectively promote the transfer of photogenerated charges at the interface and improve the adsorption of CO 2 molecules, thus leading to a remarkable enhancement in photocatalytic CO 2 reduction activity.

The efficient catalytic conversion of light-driven methane (CH4) is still very challenging. Here, the surface-reconstructed In2O3/TiO2 heterojunction photocatalyst is successfully prepared by a two-step operation of ion exchange and calcination, and the efficient selective photocatalytic conversion of CH4 is achieved. In the absence of O2, the formation rates of ethane (C2H6) and hydrogen (H2) are 68.9 and 78.6 μmol h–1 g–1, respectively, which corresponds to the stoichiometric ratio. However, in the presence of O2 or water (H2O) as the oxidant, CH4 is converted to CO, and the CO formation rates are 113.2 and 94.4 μmol h–1 g–1, respectively. Our results show that the In3–O2– Lewis acid–base pair on the In2O3/TiO2 surface can realize the adsorption and activation of CH4. Moreover, the photogenerated hole-induced reactive oxygen centers (Ti4+O·–Ti4+OH– and Ti4+O2–Ti4+O·–) on the surface of In2O3/TiO2 are identified as the active species for inducing the dissociation of CH4 into ·CH3 radicals, which in turn are coupled into C2H6 by ·CH3. In contrast, in the presence of O2, the surface superoxide anion (O2 –), surface ·O– radicals, and O2 2– anions are identified as the active species for inducing the oxidation of CH4 into CO.

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Rationally constructing high-performance electrocatalysts for the oxygen evolution reaction (OER) is a key step to increase the efficiency of the water electrolysis system. Herein, one-dimensional (1D) Co9S8/Co(OH)F heterostructures were constructed...

The rational design and engineering of threedimensional (3D) micro-/nano-architectures still remains a technological challenge for electrochemical energy storage materials. In the current work, a facile and scalable structural engineering strategy is described for the synthesis of highly crosslinked 3D ε-Fe 2 O 3 networks via an in situ manipulation of the molecular framework-engaged reactions. The as-obtained ε-Fe 2 O 3 with a large specific surface area and abundant mesopores possesses a 3D interlocked architecture organized by ultrathin nanosheets. The formation mechanism of this unique structure is explored, which is shown to be Fe(CN) 6 4− -mediated molecularlevel template action leading to the self-assembly of a 3D framework. As a conversion-type anode for LIBs, the optimized ε-Fe 2 O 3 networks exhibit a high reversible specific capacity, good rate capability, as well as long-term stability, with a reversible capacity of 953.8 mAh g −1 that is retained beyond 600 cycles at 1.0 A g −1 . In addition, the excellent Li storage performance can be ascribed to the microarchitectured ε-Fe 2 O 3 networks, which provide multiscale dimensions, mesoporous structure, some oxygen deficiencies, as well as good structural integrity upon prolonged cycling. Furthermore, the experimental results and DFT calculations showed that ε-Fe 2 O 3 was able to form a key Li 5 Fe 5 O 8−x phase during the lithiation/delithiation process, in which the structural properties of ε-Fe 2 O 3 inherently favor the intercalation of Li + ions within ε-Fe 2 O 3 , thus leading to the experimentally observed high performance rates.