Considering the increasing concerns regarding climate change, a fundamental transformation in global energy policies is imperative, particularly within the aviation sector, which is historically anchored in the consumption of fossil fuels. This perspective presents a scholarly evaluation of the progression from deep-rooted fossil-fuel-dependent technologies to innovative strategies aimed at carbon neutrality, specifically focusing on the formulation of sustainable aviation fuel from CO₂. An analytical review of the cutting-edge methodologies for CO₂-to-jet fuel conversion is provided, and the practicality of current industrial models are assessed. This perspective explores the intricate consequences of adopting such groundbreaking technologies and evaluates their technical practicability, economic feasibility, and environmental advantages. The insights obtained from this study will substantially contribute to the discussion on energy sustainability, emphasizing the synergy between sophisticated CO₂ conversion processes and the overarching goal of realizing global carbon neutrality.

Carbon nanotubes (CNTs) work as the promising components of miniature electromechanical systems due to their excellent performances from individual to bundle scales. But it’s challenging to achieve precise patterning at nanoscale resolution with controlled position and orientation. Here, we demonstrate a fluidic strategy to interlace one-dimensional (1D) ultralong CNTs into the crossed pattern in a one-step in-situ process. Semi-circular substrates of different diameters were placed in front of the growth substrate to change the path and momentum of gas flow. Such flow perturbation caused by substrates could be markedly reflected within a micro-channel reactor, which led to formation of crossed ultralong CNTs at definite positions. Furthermore, precise control over the crossing angle as well as the diameter distribution of CNTs was achieved by varying the CNT length and diameter of semi-circular substrates. Our strategy has offered a feasible route for production of crossed ultralong CNTs and will contribute to multidimensional fluidic assembly of flexible nanomaterials.

Nanomaterials with electrochemical activity are always suffering from aggregations, particularly during the high-temperature synthesis processes, which will lead to decreased energy-storage performance. Here, hierarchically structured lithium titanate/nitrogen-doped porous graphene fiber nanocomposites were synthesized by using confined growth of Li₄Ti₅O₁₂ (LTO) nanoparticles in nitrogen-doped mesoporous graphene fibers (NPGF). NPGFs with uniform pore structure are used as templates for hosting LTO precursors, followed by high-temperature treatment at 800 ℃ under argon (Ar). LTO nanoparticles with size of several nanometers are successfully synthesized in the mesopores of NPGFs, forming nanostructured LTO/NPGF composite fibers. As an anode material for lithium-ion batteries, such nanocomposite architecture offers effective electron and ion transport, and robust structure. Such nanocomposites in the electrodes delivered a high reversible capacity (164 mAh·g^–1 at 0.3 C), excellent rate capability (102 mAh·g^–1 at 10 C), and long cycling stability.

Novel inexpensive, light, flexible, and even rollup or wearable devices are required for multi-functional portable electronics and developing new versatile and flexible electrode materials as alternatives to the materials used in contemporary batteries and supercapacitors is a key challenge. Here, binder-free activated carbon (AC)/carbon nanotube (CNT) paper electrodes for use in advanced supercapacitors have been fabricated based on low-cost, industrial-grade aligned CNTs. By a two-step shearing strategy, aligned CNTs were dispersed into individual long CNTs, and then 90 wt%–99 wt% of AC powder was incorporated into the CNT pulp and the AC/CNT paper electrode was fabricated by deposition on a filter. The specific capacity, rate performance, and power density of the AC/CNT paper electrode were better than the corresponding values for an AC/acetylene black electrode. The capacity reached a maximum value of 267.6 F/g with a CNT loading of 5 wt%, and the energy density and power density were 22.5 W·h/kg and 7.3 kW/kg at a high current density of 20 A/g. The AC/CNT paper electrode also showed a good cycle performance, with 97.5% of the original capacity retained after 5000 cycles at a scan rate of 200 mV/s. This method affords not only a promising paper-like nanocomposite for use in low-cost and flexible supercapacitors, but also a general way of fabricating multi-functional paper-like CNT-based nanocomposites for use in devices such as flexible lithium ion batteries and solar cells.

Introduction of CO₂ is a facile way to tune the growth of vertically aligned double- or single-walled carbon nanotube (CNT) forests on wafers. In the absence of CO₂, a double-walled CNT convexity was obtained. With increasing concentration of CO₂, the morphologies of the forests transformed first into radial blocks, and finally into bowl-shaped forests. Furthermore, the wall number and diameter distribution of the CNTs were also modulated by varying the amount of CO₂. With increasing CO₂ concentration, CNTs with fewer wall number and smaller diameter were obtained. The addition of CO₂ is speculated to generate water and serve as a weak oxidant for high quality CNT growth. It can tune the growth rate and the morphologies of the forests, prevent the formation of amorphous carbon, and reduce the wall number of the CNTs.