d-band center engineering in metal phosphide offers promising avenues to improve hydrogen evolution reaction (HER) activity through electronic modulation. However, precise d-band regulation via theoretically feasible double heteroatom modification remains challenging. This work demonstrates a ternary metal phosphide (Fe_0.5V_0.5NiP) engineered through Fe/V integration to optimize the d-band center of nickel phosphide (Ni₂P). Combined experimental and theoretical analyses reveal that Fe and V synergistically shift the d-band center closer to the Fermi level, thereby balancing absorption/desorption of HER intermediates. Notably, V significantly reduces water dissociation energy barriers, while Fe—V cooperation optimizes hydrogen-adsorption Gibbs free energy. The Fe_0.5V_0.5NiP achieves exceptional alkaline HER performance, delivering overpotentials of 67.9 mV (10 mA/cm²) and 203.1 mV (100 mA/cm²) in 1 mol/L KOH, surpassing the benchmark Pt/C. Remarkably, it maintains stability for 100 consecutive hours without degradation. This work provides atomic-level insights on dual-heteroatom modified d-band tuning and establishes a rational design paradigm for high-performance metal phosphide electrocatalyst.

Polymer microspheres (PMs), such as polyacrylamide, have been widely applied for enhanced oil recovery (EOR), yet with environmental concerns. Here, we report a microfluid displacement technology containing a bio-based eco-friendly material, i.e., calcium alginate (CaAlg) microspheres for EOR. Two dominant mechanisms responsible for EOR over CaAlg fluid have been verified, including the microscopic oil displacement efficacy augmented by regulating capillary force (determined by the joint action of interfacial tension and wettability between different phases) and macroscopic sweep volume increment through profile control and mobility ratio reduction. This comprehensive effectiveness can be further impacted when the CaAlg microsphere is embellished ulteriorly by using appropriate amount of sodium dodecyl sulfonate (SDS). The core flooding and nuclear magnetic resonance (NMR) tests demonstrate that CaAlg-SDS microsphere can balance the interphase property regulation (wettability alteration and IFT reduction) and rheology properties, enabling simultaneous profile control and oil displacement. Excessive introduction of SDS will have a negative impact on rheological properties, which is not favored for EOR. Our results show that the involvement of 4-mM SDS will provide the best behavior, with an EOR rate of 34.38%. This cost-effective and environmentally-friendly bio-microsphere-based microfluidic displacement technology is expected to achieve “green” oil recovery in future oilfield exploitation.