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The search for earth abundant, efficient and stable electrocatalysts that can enable the chemical reduction of CO2 to value-added chemicals and fuels at an industrially relevant scale, is a high priority for the development of a global network of renewable energy conversion and storage systems that can meaningfully impact greenhouse gas induced climate change. Here we introduce a straightforward, low cost, scalable and technologically relevant method to manufacture an all-carbon, electroactive, nitrogen-doped nanoporous carbon-carbon nanotube composite membrane, dubbed "HNCM-CNT". The membrane is demonstrated to function as a binder-free, high-performance electrode for the electrocatalytic reduction of CO2 to formate. The Faradaic efficiency for the production of formate is 81%. Furthermore, the robust structural and electrochemical properties of the membrane endow it with excellent long-term stability.

CdS/graphene composite photocatalysts were prepared by photocatalytically reducing graphene oxide with CdS nanoparticles in an aqueous ethanol solution. The structure and photoelectrical properties of the resulted materials were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and transient photocurrent measurements. The photocatalytic activities of the CdS/graphene composites for hydrogen evolution were evaluated under visible light irradiation (λ≥420 nm). The results show that the graphene oxide can be efficiently reduced by the photogenerated electrons of CdS and thus CdS/graphene composite is formed and it shows strong interactions between CdS and graphene. Compared with CdS, the enhanced photocurrent generation and photocatalytic activity toward hydrogen evolution for the CdS/ graphene composite photocatalysts could be attributed to the ability of graphene to capture and transport electrons, and to promote charge separation.

Fibrillar conductive polyaniline/TiO2 (PANI/TiO2) nanocomposites with different TiO2 amount were synthesized with a template-free in situ polymerization method and characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and conductivity measurement. The morphology determination shows that the PANI/TiO2 composite nanofibers are relatively uniform with the diameter and length in the range of 20–40 nm and 390–420 nm respectively. It also shows that the TiO2 of the composite is rutile crystalline and PANI has some degree of crystallinity. The IR measurement indicates that there is a strong interaction between the PANI and TiO2 nanoparticles, and it has a beneficial effect on the thermal stability of the composite nanofiber. The conductivity of PANI/TiO2 composites changes with TiO2 amount and reaches an optimum value of 2.86 S/cm at 11.1 wt% TiO2.