NH3 has been used in wide applications, such as fertilizers, hydrogen sources, and working fluids, where proper NH3 adsorbents are required to minimize human health risks in daily NH3 exposure as well as to achieve energy efficiency in energy conversion systems. As NH3 operating pressure differs from each usage, the structure and properties of the NH3 adsorbent need to be optimized in each NH3 operating pressure. Metal–organic frameworks (MOFs) have emerged as promising NH3 adsorbents, which would be customizable for different NH3 pressures due to great structural tunability. We introduce up‐to‐date reports with MOFs as NH3 adsorbents and classify them by the NH3 pressure, from high in adsorption heat pumps to extremely low in daily life sensing. MOFs with high NH3 adsorption capacity and durability are suggested in different NH3 pressure ranges, and their structural factors are discussed to help design high‐performance MOFs for NH3 adsorption in different NH3 pressures.
Ammonia has emerged
as a potential working fluid in adsorption
heat pumps (AHPs) for clean energy conversion. It would be necessary
to develop an efficient adsorbent with high-density ammonia uptake
under high gas pressures in the low-temperature range for waste heat.
Herein, a porous nanocomposite with MIL-101(Cr)-NH
2
(MIL-A)
and reduced graphene oxide (rGO) was developed to enhance the ammonia
adsorption capacity over high ammonia pressures (3–5 bar) and
low working temperatures (20–40 °C). A one-pot hydrothermal
reaction could form a two-dimensional sheet-like nanocomposite where
MIL-A nanoparticles were well deposited on the surface of rGO. The
MIL-A nanoparticles were shown to grow on the rGO surface through
chemical bonding between chromium metal centers in MIL-A and oxygen
species in rGO. We demonstrated that the nanocomposite with 2% GO
showed higher ammonia uptake capacity at 5 bar compared with pure
MIL-A and rGO. Our strategy to incorporate rGO with MIL-A nanoparticles
would further be generalizable to other metal–organic frameworks
for improving the ammonia adsorption capacity in AHPs.
The lattice strain effect in Pd–Ni core–shell nanocubes on the selectivity of urea electrolysis is elucidated, which can facilitate catalyst design for efficient urea waste treatment and concomitant cathodic hydrogen production or CO2 reduction.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.