Defective Zr-Fumarate MOFs Enable High-Efficiency Adsorption Heat Allocations

Adsorption-driven
heat transfer devices incorporating an efficient
“adsorbent–water” working pair are attracting
great attention as a green and sustainable technology to address the
huge global energy demands for cooling and heating. Herein, we report
the improved heat transfer performance of a defective Zr fumarate
metal–organic framework (MOF) prepared in a water solvent (Zr-Fum HT). This material exhibits an S-shaped water sorption
isotherm (P/P0 = 0.05–0.2),
excellent working capacity (0.497 mLH2O mL–1MOF) under adsorption-driven cooling/chiller
working conditions (Tadsorption(ads) =
30 °C, Tcondensation (con) =
30 °C, and Tdesorption(des) = 80
°C), very high coefficient of performances for both cooling (0.83)
and heating (1.76) together with a relatively low driving temperature
at 80 °C, a remarkable heat storage capacity (423.6 kW h m–3MOF), and an outstanding evaporation heat
(343.8 kW h m–3MOF). The level of performance
of the resultant Zr-Fum HT MOF is above those of
all existing benchmark water adsorbents including MOF-801 previously
synthesized in the N,N-dimethylformamide
solvent under regeneration at 80 °C which is accessible from
the solar source. This is coupled with many other decisive advantages
including green synthesis and high proven chemical and mechanical
robustness. The microscopic water adsorption mechanism of Zr-Fum HT at the origin of its excellent water adsorption
performance was further explored computationally based on the construction
of an atomistic defective model online with the experimental data
gained from a subtle combination of characterization techniques.