Metal organic frameworks (MOFs) have emerged as promising candidates for atmospheric water harvesting due to their high porosity and tunable functionality. Among diverse MOFs

MOF-303 has demonstrated excellent water adsorption capacity

rapid desorption kinetics and structural stability. Nevertheless

its practical application is still limited by the time-consuming synthesis process and difficulties in morphological control. To overcome these challenges

a surfactant-mediated microwave-assisted strategy was proposed. Compared to conventional heating methods

microwave irradiation reduced the reaction duration from 24 h to 1 h with a 13% increase in product yield (from 76% to 89%). However

the accelerated nucleation under microwave irradiation resulted in smaller crystal dimensions (from 50 nm ± 10 nm to 35 nm ± 10 nm)

therefore inducing severe particle agglomeration. To mitigate this morphological drawback

systematic investigations were conducted to evaluate the effects of surfactants’ species on

crystal growth. Among the selected surfactants

poly(sodium-

p

-styrene sulfonate) (PSS) was identified as an effective morphology-directing agent

achieving uniform crystal sizes with improved monodispersity through preferential adsorption on specific crystallographic planes of the MOF. Subsequent optimization of synthetic conditions

including temperature (120-160 °C)

reaction time (15 min-1 h)

and surfactant concentration

yielded MOF-303 with a yield of 96.37%

with particle uniformity of (35 nm ± 10 nm) and predominantly blocky crystal morphology. Water adsorption measurements confirmed that the surfactant-modified MOF-303 retained comparable performance to the surfactant-free counterpart

with a maximum capacity (water/MOF) of 0.214 g·g

-1

at 35% RH. This study establishes a scalable and tunable synthetic protocol for MOF-303

providing critical insights into microwave-accelerated crystal engineering.