Search

Photocatalytic valorization and selective transformation of biomass‐derived platform compounds offer great opportunities for efficient utilization of renewable resources under mild conditions. Here, the novel three‐dimensional hierarchical flower‐like CdS/Ti3C2 Schottky junction (MCdS) composed of surface‐controlled CdS and pretreated Ti3C2 MXene is created for photocatalytic dehydrogenation‐reductive amination of biomass‐derived amino acid production under ambient temperature with unprecedented activity and selectivity. Schottky junction efficiently promotes photoexcited charge migration and separation and inhibits photogenerated electron‐hole recombination, which results in a super‐high activity. Meanwhile, CdS with the reduced surface energy supplies sufficient hydrogen sources for imine reduction and induces the preferential orientation of alanine, thus contributing superior selectivity. Moreover, a wide range of hydroxyl acids are successfully converted into corresponding amino acids and even one‐pot conversion of glucose to alanine is easily achieved over MCdS. This work illustrates the mechanism of crystal orientation control and heterojunction construction in controlling catalytic behavior of photocatalytic nanoreactor, providing a paradigm for construction of MXene‐based heterostructure. [ABSTRACT FROM AUTHOR]

Sluggish CO2 reduction/evolution kinetics at cathodes seriously impede the realistic applications of Li–CO2 batteries. Herein, synergistic photoelectric effect and plasmonic interaction are introduced to accelerate CO2 reduction/evolution reactions by designing a silver nanoparticle‐decorated titanium dioxide nanotube array cathode. The incident light excites energetic photoelectrons/holes in titanium dioxide to overcome reaction barriers, and induces the intensified electric field around silver nanoparticles to enable effective separation/transfer of photogenerated carriers and a thermodynamically favorable reaction pathway. The resulting Li–CO2 battery demonstrates ultra‐low charge voltage of 2.86 V at 0.10 mA cm−2, good cycling stability with 86.9 % round‐trip efficiency after 100 cycles, and high rate capability at 2.0 mA cm−2. This work offers guidance on rational cathode design for advanced Li–CO2 batteries and beyond. [ABSTRACT FROM AUTHOR]

Li−CO2 batteries are explored as promising power systems to alleviate environmental issues and to implement space applications. However, sluggish cathode kinetics of CO2 reduction/evolution result in low round‐trip efficiency and poor cycling stability of the fabricated energy‐storage devices. Herein, we design a heterostructued photocathode comprising carbon nanotube and carbon nitride to accelerate cathode reactions of a Li−CO2 battery under illumination. Benefiting from the unique defective structure of carbon nitride and favorable interfacial charge transfer, the photocathode effectively harvests ultraviolet‐visible light to generate abundant photoexcited carriers and coordinates energetic photoelectrons/holes to participate in the discharge/charge reactions, leading to efficient photo‐energy utilization in decreasing reaction barriers and enhancing thermodynamic reversibility of Li−CO2 battery. The resulting battery delivers a high round‐trip efficiency of 98.8 % (ultralow voltage hysteresis of 0.04 V) and superior cycling stability (86.1 % efficiency retention after 100 cycles). [ABSTRACT FROM AUTHOR]

Achieving high‐current‐density and high‐area‐capacity operation of Li metal anodes offers promising opportunities for high‐performing next‐generation batteries. However, high‐rate Li deposition suffers from undesired Li‐ion depletion especially at the electrolyte‐anode interface, which compromises achievable capacity and lifetime. Here, electronegative graphene quantum dots are synthesized and assembled into an ultra‐thin overlayer capable of efficient Li‐ion adsorbing at the nanoscale on Li‐metal to fully relieve Li‐ion depletion. The protected Li anode achieves long‐term reversible Li plating/stripping over 1000 h at both superior current density of 60 mA cm−2 and areal capacity of 60 mAh cm−2. Implementation of the protected anode allows for the construction of Li‐air full battery with both enhanced rate capability and cycling performance. [ABSTRACT FROM AUTHOR]