Cellulose nanocrystal-templated melamine-formaldehyde nanorods were fabricated via in situ polycondensation followed by a one-step carbonization into hierarchically porous carbon that possessed promising supercapacitive performance.

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The highly infectious coronavirus disease 2019 (COVID-19) associated with the pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread to become a global pandemic. At present, the world is relying mainly on containment and hygiene-related measures, as well as repurposed drugs to control the outbreak. The development of COVID-19 vaccines is crucial for the world to return to pre-pandemic normalcy, and a collective global effort has been invested into protection against SARS-CoV-2. As of March 2021, thirteen vaccines have been approved for application whilst over 90 vaccine candidates are under clinical trials. This review focuses on the development of COVID-19 vaccines and highlights the efficacy and vaccination reactions of the authorised vaccines. The mechanisms, storage, and dosage specification of vaccine candidates at the advanced stage of development are also critically reviewed together with considerations for potential challenges. Whilst the development of a vaccine is, in general, in its infancy, current progress is promising. However, the world population will have to continue to adapt to the “new normal” and practice social distancing and hygienic measures, at least until effective vaccines are available to the general public.

This paper describes a novel platform to prepare small and uniformly distributed metal nanoparticles (MNPs) on cellulose nanocrystals for use as high performance sustainable nanocatalysts. The model platinum or palladium NPs (1−2 nm in size) were immobilized and chemically reduced onto melamine-formaldehyde (MF) coated cellulose nanocrystals (MFCNCs). The MF coating was critical for the uniform generation and size-control of MNPs. The contribution of MF resin to optimal MNP synthesis includes: (1) increased surface area with its spongelike structure, (2) enhanced affinity to metals through chelation with nitrogen functionalities, and (3) effective MNP size control due to the mesoporous structure. The MNP/MFCNC system significantly improved catalytic activity as demonstrated by the reduction of 4-nitrophenol with Pd/MFCNCs with a turnover frequency of 3168 h −1 . Our synthesis does not require any complicated apparatus or harsh reaction conditions. The proposed strategy is well-suited for the synthesis of a wide range of metal nanocatalysts characterized by a particle size of 1 to 2 nm and superior catalytic activity.

A facile method of polymerizing polypyrrole (PPy) on poly(N-vinylpyrrolidone) (PVP) coated cellulose nanocrystals (CNCs) was developed.