Ni2P/biocarbon composite derived from an unusual phosphorus-rich precursor as a superior catalyst for 4-nitrophenol reduction

Conversion of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) through advanced reduction process is important to lower the hazardous risk of 4-NP, which requires the development of highly efficient catalyst. Herein, we proposed a novel strategy to fabricate nickel phosphide/carbon composite for 4-NP reduction in the presence of NaBH4. An unusual precursor of adenosine 5′-triphosphate (ATP) was applied to provide the essential phosphorus and carbon elements for nickel phosphide and biocarbon, respectively. ATP-Ni complex was firstly prepared and then transformed to nickel phosphide/biocarbon composite by an anoxic pyrolysis treatment. Material characterizations confirmed both large particles of hundreds of nanometers and small particles of ∼2.4 nm existing for Ni2P, which were dispersed on N/P-doped biocarbon with thin layer sheet-like structure. When applied for 4-NP reduction, Ni2P/BC exhibited fast reaction kinetic with a pseudo-first-order reaction rate constant of 0.019 s−1 (normalized rate constant 253 s−1 g−1) and good reusability in 10 consecutive reaction runs (95.8% conversion efficiency). It is suggested that such superior activity may originate from the high affinity of Ni2P/BC towards reactants and the good electron transfer ability of Ni2P/BC. This study not only enriches the synthesis strategy of transition metal phosphide, but also provides a superior catalyst for advanced reduction process.