The role of N-heterocyclic carbene, a well-known reactive site, in chemical catalysis has long been studied. However, its unique binding and electron-donating properties have barely been explored in other research areas, such as metal capture. Herein, we report the design and preparation of a poly(ionic liquid)-derived porous organic polycarbene adsorbent with superior gold-capturing capability. With carbene sites in the porous network as the “nanotrap”, it exhibits an ultrahigh gold recovery capacity of 2.09 g/g. In-depth exploration of a complex metal ion environment in an electronic waste-extraction solution indicates that the polycarbene adsorbent possesses a significant gold recovery efficiency of 99.8%. X-ray photoelectron spectroscopy along with nuclear magnetic resonance spectroscopy reveals that the high performance of the polycarbene adsorbent results from the formation of robust metal-carbene bonds plus the ability to reduce nearby gold ions into nanoparticles. Density functional theory calculations indicate that energetically favourable multinuclear Au binding enhances adsorption as clusters. Life cycle assessment and cost analysis indicate that the synthesis of polycarbene adsorbents has potential for application in industrial-scale productions. These results reveal the potential to apply carbene chemistry to materials science and highlight porous organic polycarbene as a promising new material for precious metal recovery.

Unexpected intercalation-dominated process is observed during K⁺ insertion in WS₂ in a voltage range of 0.01–3.0 V. This is different from the previously reported two-dimensional (2D) transition metal dichalcogenides that undergo a conversion reaction in a low voltage range when used as anodes in potassium-ion batteries. Charge/discharge processes in the K and Na cells are studied in parallel to demonstrate the different ion storage mechanisms. The Na⁺ storage proceeds through intercalation and conversion reactions while the K⁺ storage is governed by an intercalation reaction. Owing to the reversible K⁺ intercalation in the van der Waals gaps, the WS₂ anode exhibits a low decay rate of 0.07% per cycle, delivering a capacity of 103 mAh·g^-1 after 100 cycles at 100 mA·g-¹. It maintains 57% capacity at 800 mA·g^-1 and shows stable cyclability up to 400 cycles at 500 mA·g-¹. Kinetics study proves the facilitation of K⁺ transport is derived from the intercalation-dominated mechanism. Furthermore, the mechanism is verified by the density functional theory (DFT) calculations, showing that the progressive expansion of the interlayer space can account for the observed results.