Triphenyl Phosphite as the Phosphorus Source for the Scalable and Cost-Effective Production of Transition Metal Phosphides

Abstract

Transition metal phosphides have great potential to optimize a number of functionalities in several energy conversion and storage applications, particularly when nanostructured or in nanoparticle form. However, the synthesis of transition metal phosphide nanoparticles and its scalability is often limited by the toxicity, air sensitivity and high cost of the reagents used. We present here a simple, scalable and cost-effective 'heating up' procedure to produce metal phosphides using inexpensive, lowtoxicity and air-stable triphenyl phosphite as source of phosphorous and chlorides as metal precursors. This procedure allows the synthesis of a variety of phosphide nanoparticles, including phosphides of Ni, Co and Cu. The use of carbonyl metal precursors further allowed the synthesis of Fe 2 P and MoP nanoparticles. The fact that minor modifications in the experimental parameters allowed producing nanoparticles with different compositions and even to tune their size and shape, shows the high potential and versatility of the triphenyl phosphite precursor and the presented method. We also detail here a methodology to displace organic ligands from the surface of phosphide nanoparticles which is a key step towards their application in energy conversion and storage systems. 1. INTRODUTION Transition metal phosphides (TMP) are widely used in ion battery anodes 1-4 , as absorbers in photovoltaics 5 , supercapacitors 6 and as a catalysts in several processes including hydroprocessing 7-13 , water-gas-shift reaction, 14 and water splitting, 15-19 replacing costly and scarce noble metal catalysts. In spite of their high potential, reports on catalytic properties of fairly well-shaped phosphide nanoparticles (NPs) are scarce, 13, 20-27 and generally carbon based nanostructures, decorated with phosphide nanoparticles have been tested as catalysts. Actually, very few routes for the synthesis of TMP nanoparticles with some control over their parameters exist. 28,29 These previous works described the synthesis of phosphides of

Precious‐Metal‐Free Electrocatalysts for Activation of Hydrogen Evolution with Nonmetallic Electron Donor: Chemical Composition Controllable Phosphorous Doped Vanadium Carbide MXene

“…After heat treatment at 300 °C (P1‐V 2 CT x ), it shows the visible peaks of P 2p, which is assigned to be PO 133.5 eV (P 2p 3/2 ), 134.4 eV (P 2p 1/2 ), and very little peak of PC at 130.5 eV (P 2p 3/2 ), 132.1 eV (P 2p 1/2 ) . In previous results for synthesizing the transition metal phosphide (Ni, Co, and Fe), they used to perform the reaction at above 300 °C . However, it is confirmed that reactivity of V 2 CT x to phosphine (PH 3 ) is low at 300 °C, as only the PO (phosphorous oxide) prominently appears, while there is a peak of PC with small intensity, which means that P‐oxide is formed easily by oxidation or decomposition of TPP at 300 °C rather than formation of chemical doping states.…”

Phase Directing Ability of an Ionic Liquid Solvent for the Synthesis of HER-Active Ni2P Nanocrystals

“…[9][10][11] The binary Ni-P phase diagram is complex, with a large number of thermodynamically stable stoichiometries (Ni 3 P, Ni 5 P 2 , Ni 12 P 5 , Ni 2 P, Ni 5 P 4 , NiP, NiP 2 , and NiP 3 ), thereby creating a synthetic challenge with respect to accessing phase-pure Ni 2 P. In general, increasing the molar equivalents of phosphide precursor, extending the reaction time, and operating at higher temperatures allow the more phosphorus-rich side of the phase diagram to be accessed for colloidal nanocrystals. [12][13][14] Typical methods used to synthesize high-quality colloidal Ni 2 P nanocrystals use traditional organic solvents (e.g., octadecene (ODE), dioctyl ether), expensive and/or reactive phosphide precursors (tri-n-octylphosphine (TOP), white phosphorus (P 4 ), tris(trimethylsilyl)phosphine (P(TMS) 3 ), and tri-n-butylphosphine), high temperatures, and/or multiple-step reactions. 10,[15][16][17] Triphenylphosphine (PPh 3 ) is a low-cost, less-reactive, and more air-stable phosphide precursor (~15% the cost of TOP in price per mole); 18 however, compared to TOP and P(TMS) 3 , nanocrystals synthesized using PPh 3 are typically large (>45 nm), ill-defined, amorphous, and/or not phase pure.…”

Topochemical Synthesis of Two‐Dimensional Transition‐Metal Phosphides Using Phosphorene Templates

“…[28] The P atoms neighboring the vacancies continue to react with DMF molecules according to Equation (2). Afterwards, the growth of the 2D TMPs involves two steps: [29] First, reduction of the metal ions to the metal (M) at hydrogenated P vacancies [Eq. (3)] followed by phosphidation of the metal clusters at the phosphorene interfaces…”