Charge-Directed Nanocellulose Assembly for Interfacial Phase-Transfer Catalysis

Abstract

Liquid–liquid interfaces present unique opportunities for sustainable biphasic catalysis, yet concurrent amplification of molecular transport and reactivity at these boundaries remains challenging. Here it is demonstrated that high-aspect-ratio cationic nanocellulose (HNC⁺) spontaneously self-assembles into mechanically robust nanomesh architectures at oil-water interfaces through charge-directed assembly. This assembly is driven by electrostatic attraction between the cationic nanofibers and the intrinsic negative charge at hydrophobic-aqueous interfaces (σ ≈−0.3 C m⁻²), generating sufficient excess attractive force (ΔU ≈−1,200 k_BT) to overcome image charge repulsion. The resulting nanomesh exhibits uniform “breathing holes” (≈34 nm) and exceptional stability under extreme conditions (pH 2–13, 1.8 m NaCl, and 90 °C). When applied to oxidative desulfurization, the system achieves >90% thiophene removal under ambient conditions with exceptional atom economy (E-factor < 1.1) and catalyst stability through multiple cycles. This breakthrough strategy for interfacial engineering using renewable materials opens new possibilities for green chemical manufacturing while providing fundamental insights into charge-mediated assembly at liquid interfaces. These findings establish a viable pathway for sustainable heterogeneous catalysis that aligns with circular economy principles.