In response to the rapid development of highly integrated multifunctional electronic devices, developing advanced multifunctional composite phase change materials (PCMs) that integrate thermal management, solar-thermal conversion and microwave absorption has become increasingly essential. Herein, we propose a bionical strategy to design neural network-like (carbon nanofiber) CNF@Co/C aerogels by growing ZIF-67 in situ on bacterial cellulose (BC) and subsequent calcination strategies. After the encapsulation of thermal storage unit (paraffin wax, PW), the obtained multifunctional composite PCMs (PW-CNF@Co/C aerogel) are composed of “soma” (Co/C polyhedra), “axon” (porous CNF) and thermal storage unit (PW). Importantly, the composite PCMs show a high solar-thermal conversion efficiency of 95.27% benefiting from the synergism of “soma” with strong local surface plasmon resonance (LSPR) effect and “axon” with enhanced photon transmission path. More attractively, the composite PCMs also display good microwave absorption capacity with a minimum reflection loss (RL) of -26.8 dB at 10.91 GHz owing to the synergy of magnetic and dielectric components along with abundant polarization and multiple reflections. Our developed functionally integrated composite PCMs provide a prospective application of highly integrated and miniaturized electronic devices in complex and changeable outdoor environments.

Advanced multifunctional composite phase change materials (PCMs) for integrating energy storage, photothermal conversion and microwave absorption can promote the development of next-generation miniaturized electronic devices. Here, we report paraffin wax (PW)-based multifunctional composite PCMs with a hierarchical network structure assembled by two‐dimensional (2D) nickel-based metal-organic frameworks (Ni-MOFs) decorated carbon nanotubes (CNTs). The PW/CNTs@Ni-MOF composite PCMs yield an excellent photothermal energy conversion efficiency of 93.2%, as well as a good phase change enthalpy of 126.5 J/g and prominent thermal stability. Preferably, the composite PCMs also present great microwave absorption with –25.32 dB minimum reflection loss (RL_min) at 9.85 GHz. The remarkable features of the composite PCMs lie in their hierarchical network architecture and the synergistic enhancement of CNTs and MOFs, giving rise to the increased surface area, accelerated photon capture and transmission, and enhanced dielectric loss caused by polarization effects and multiple reflections, thus further boosting the latent energy storage capacity, photothermal kinetics, and microwave reflection loss. This work provides a facile and scalable approach to regulating the multifunction of composite PCMs.

Efficient hydrogen production via photocatalysis with high utilization efficiency of Pt cocatalyst is of great importance for sustainable development. In this work, we report an in situ auto-reduction strategy to encapsulate highly dispersed Pt clusters inside the cages of MIL-125-NH₂. The amino groups in MIL-125-NH₂ first react with formaldehyde to form reducing groups (i.e., –NH-CH₂OH), which can in situ auto-reduce the confined Pt²⁺ ions to ultrasmall Pt clusters within the cavities. With optimized Pt content, photocatalytic H₂ production over the obtained Pt(1.5)/MIL-125-NH-CH₂OH catalyst with 1.43 wt.% Pt loading achieved as high as 4, 496.4 µmol·g⁻¹·h⁻¹ under visible light (λ > 420 nm) due to the facilitated transfer and separation of the photo-induced charger carriers arising from the synergetic effects between highly dispersed Pt clusters and MIL-125-NH-CH₂OH framework. This in situ auto-reduction strategy may be extended to encapsulate various kinds of metal or alloy clusters/nanoparticles within amino-functioned metal-organic frameworks (MOFs) with superior properties and excellent performance.