NiFe-Loaded Self-Supporting Carbon Nanotubes Electrode for Hydrogen Evolution Reaction Via <i>in Situ</i> Catalytic Carbonization of Waste Polypropylene

In recent years, the amount of waste polypropylene (WPP) has increased massively due to the widespread use of PP in various industries, such as packaging, automotive, and construction. How to make resourceful use of the WPP is a question worth considering for researchers. Herein, a self-supporting carbon nanotubes (CNTs) electrode for hydrogen evolution reaction (HER) has been prepared via in-situ catalytic pyrolysis carbonization of WPP. Nickel foam (NF) with NiFe(OH)[Formula: see text] pyrolysis catalyst (NiFe@NF) prepared by a simple immersion method, is used as a current collector and electrode support. Then, the NiFe-loaded self-supporting carbon nanotubes electrode (CNT-NiFe@NF) is obtained through calcining NiFe@NF and WPP together. Characterization analyses show that amorphous NiFe(OH)[Formula: see text] with patterned nanosheets is generated on the surface of NF. After calcining with WPP, uniformly shaped carbon nanotubes with a tube diameter of about 38[Formula: see text]nm are formed on NF. The electrochemical tests in 1[Formula: see text]M KOH solution show that the as-prepared CNT-NiFe@NF electrode exhibits excellent electrocatalytic performance of HER, and with a low overpotential of 98[Formula: see text]mV. In comparison with NF and control group samples, CNT-NiFe@NF shows the smallest Tafel slope (96[Formula: see text]mV dec[Formula: see text] and best stability in the 10[Formula: see text]h chronopotential test.