Graphdiyne (GDY), a new kind of two-dimensional (2D) carbon allotropes, has extraordinary electrical, mechanical, and optical properties, leading to advanced applications in the fields of energy storage, photocatalysis, electrochemical catalysis, and sensors. However, almost all reported methods require metallic copper as a substrate, which severely limits their large-scale application because of the high cost and low specific surface area (SSA) of copper substrate. Here, freestanding three-dimensional GDY (3DGDY) is successfully prepared using naturally abundant and inexpensive diatomite as template. In addition to the intrinsic properties of GDY, the fabricated 3DGDY exhibits a porous structure and high SSA that enable it to be directly used as a lithium-ion battery anode material and a 3D scaffold to create Rh@3DGDY composites, which would hold great potential applications in energy storage and catalysts, respectively.

PAPER Jinglei Lei et al.A one-step, cost-eff ective green method to in situ fabricate Ni(OH) 2 hexagonal platelets on Ni foam as binder-free supercapacitor electrode materials Nickel hydroxide (Ni(OH) 2 ) is considered to be a promising alternative to the expensive and toxic RuO 2 electrode material for high-performance supercapacitors; however, the fabrication method and electrochemical performance of suitable Ni(OH) 2 structures are unsatisfactory. In the present work, a facile, cost-effective green method is developed to in situ fabricate Ni(OH) 2 hexagonal platelets on Ni foam as a binder-free supercapacitor electrode with high performance. The Ni(OH) 2 hexagonal platelets are self-grown on three-dimensional (3D) Ni foam by a one-step hydrothermal treatment of Ni foam in a 15 wt% H 2 O 2 aqueous solution without the use of nickel salts, acids, bases, or post-treatments. The asprepared Ni(OH) 2 hexagonal platelets-Ni foam (HNF) electrode can be used directly as a supercapacitor electrode material, thereby avoiding the need for binders and conducting agents. The Ni(OH) 2 hexagonal platelets demonstrate high capacitance (2534 F g À1 at a scan rate of 1 mV s À1 ) and excellent cycling stability (97% capacitance retention after 2000 cycles at a scan rate of 50 mV s À1 ). The fabrication method developed here has the significant advantage of low-cost, facile, green, and additive-free processing, and it is therefore a promising route for preparing self-supported metal (hydr)oxide electrodes for high-performance supercapacitors and other energy-storage devices.

Reducing CO2 into fuels via photochemical reactions relies on highly efficient photocatalytic systems. Herein, we report a new and efficient photocatalytic system for CO2 reduction. Driven by electrostatic attraction, an anionic metal–organic framework Cu-HHTP (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene) as host and a cationic photosensitizer [Ru­(phen)3]2+ (phen = 1,10-phenanthroline) as guest were self-assembled into a photocatalytic system Ru@Cu-HHTP, which showed high activity for photocatalytic CO2 reduction under laboratory light source (CO production rate of 130(5) mmol g–1 h–1, selectivity of 92.9%) or natural sunlight (CO production rate of 69.5 mmol g–1 h–1, selectivity of 91.3%), representing the remarkable photocatalytic CO2 reduction performance. More importantly, the photosensitizer [Ru­(phen)3]2+ in Ru@Cu-HHTP is only about 1/500 in quantity reported in the literature. Theoretical calculations and control experiments suggested that the assembly of the catalysts and photosensitizers via electrostatic attraction interactions can provide a better charge transfer efficiency, resulting in high performance for photocatalytic CO2 reduction.

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