Optimized TiO2/CuxO/C nanocomposites derived from bi-MOF NH2-MIL-125(Ti/Cu) with in situ formed p–n heterojunctions exhibited superior photocatalytic HER performance without noble metals.

Surface-functionalized nitrogen/carbon co-doped polymorphic TiO 2 phase junction nanoparticles uniformly distributed in porous carbon matrix were synthesized by a simple one-step pyrolysis of titanium based metal-organic framework (MOF), NH 2 -MIL-125(Ti) at 700°C under water vapour atmosphere. Introducing water vapour during the pyrolysis of NH 2 -MIL-125(Ti) not only functionalizes the derived porous carbon matrix with carboxyl groups but also forms additional oxygen-rich N like interstitial/intraband states lying above the valence band of TiO 2 along with the self-doped carbon, which further narrows the energy band gaps of polymorphic TiO 2 nanoparticles that enhance photocatalytic charge transfer efficiency. Without co-catalyst, sample N-C-TiO 2 /C ArW demonstrates H 2 evolution activity of 426 mmol g cat -1 h À1 , which remarkably outperforms commercial TiO 2 (P-25) and N-C-TiO 2 /C Ar with a 5-fold and 3-fold H 2 generation, respectively. This study clearly shows that water vapour atmosphere during the pyrolysis increases the hydrophilicity of the Ti-MOF derived composites by functionalizing porous carbon matrix with carboxylic groups, as well as enhancing the electrical conductivity and charge transfer efficiency due to the formation of additional localized oxygen-rich N like interstitial/intraband states. This work also demonstrates that by optimizing the anatase-rutile phase composition of the TiO 2 polymorphs, tuning the energy band gaps by N/C co-doping and functionalizing the porous carbon matrix in the N-C-TiO 2 / C nanocomposites, the photocatalytic H 2 generation activity can be further enhanced.

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Solar energy is a key sustainable energy resource, and materials with optimal properties are essential for efficient solar energy-driven applications in photocatalysis. Metal-organic frameworks (MOFs) are excellent platforms to generate different nanocomposites comprising metals, oxides, chalcogenides, phosphides, or carbides embedded in porous carbon matrix. These MOF derived nanocomposites offer symbiosis of properties like high crystallinities, inherited morphologies, controllable dimensions, and tunable textural properties. Particularly, adjustable energy band positions achieved by in situ tailored self/external doping and controllable surface functionalities make these nanocomposites promising photocatalysts. Despite some progress in this field, fundamental questions remain to be addressed to further understand the relationship between the structures, properties, and photocatalytic performance of nanocomposites. In this review, different synthesis approaches including self-template and external-template methods to produce MOF derived nanocomposites with various dimensions (0D, 1D, 2D, or 3D), morphologies, chemical compositions, energy bandgaps, and surface functionalities are comprehensively summarized and analyzed. The state-of-the-art progress in the applications of MOF derived nanocomposites in photocatalytic water splitting for H 2 generation, photodegradation of organic pollutants, and photocatalytic CO 2 reduction are systemically reviewed. The relationships between the nanocomposite properties and their photocatalytic performance are highlighted, and the perspectives of MOF derived nanocomposites for photocatalytic applications are also discussed.

The serious shuttle effect of lithium‐sulfur batteries limits the efficient realization of high rate charging and discharging under high sulfur loading in practical applications. Herein, this work reports a strong mitigation toward lithium polysulfide (LiPSs) adsorption/catalysis by introducing defective graphite phase carbon nitride (g‐C3N4) as an effective additive. Without significant weight increase, the nitrogen deficient g‐C3N4, in the form of ultrafine spindle‐like nitrogen deficient g‐C3N4−x (sCN), can be easily combined with commercial poly‐propylene (PP) separators after hydrophilic modification of polydopamine, which corresponds to an ultralow overall weightiness contribution of 0.17 mg cm−2. Physical/electrochemical characterizations and theoretical studies reveal that sCN exhibits strong electrostatic attraction with LiPSs by nitrogen defects and new formation of cyano groups near edges, thereby maintaining rapid and reliable LiS electrochemistry. Of particular importance is the chainmail catalyst design with separators that enable magic polysulfides adsorption effect and desirable thermostability/wettability, which guarantees the sCNPP‐assembled cells with long and stable durability over 500 cycles at 5.0 C (capacity fading rate: 0.05% per cycle), and a high capability of 476 mAh g−1 is obtained.