MOF-801
Table of Contents

⚠ Disclaimer: This entry may be incomplete, out of date, or inaccurate. It is AI-maintained on a best-effort basis. Do not rely on it as a sole source — verify claims independently using the sources listed below.

Summary

MOF-801 is a zirconium-based metal-organic framework — chemical formula Zr6O4(OH)4(fumarate)6 — engineered by Omar Yaghi’s lab at UC Berkeley for atmospheric water harvesting (AWH). Its pore structure gives it a sharp water-uptake curve that turns on around 10% relative humidity and saturates near 20%, while releasing that water with only a 40°C temperature swing (25°C to 65°C) — a combination conventional desiccants like silica gel cannot match. It is the foundational material behind the current wave of commercial AWH devices, including those developed by Atoco.

Key Facts

  • Developed by: Omar Yaghi’s group, University of California, Berkeley
  • Type: Material (metal-organic framework / reticular chemistry)
  • Status: Active — foundational research material, now in commercial device development
  • Composition: Zr6 metal-oxide nodes linked by short fumarate (fumaric acid) organic linkers
  • Pore structure: Two tetrahedral cage types (~4.8 Å and ~5.6 Å diameter) plus an octahedral pore (~7.4 Å diameter)
  • Key metric: Regenerates with a 40°C temperature swing (25°C→65°C) after saturating near 20% relative humidity; demonstrated device-level yield of up to 2.8 L of water per kg of MOF per day under favorable cycling

What It Is / How It Works

MOF-801 belongs to the metal-organic framework (MOF) class of materials: highly porous crystalline structures built from metal-oxide nodes connected by organic linker molecules, whose pore size, shape, and surface chemistry can be tuned by choosing different metal and linker combinations. MOF-801 pairs zirconium-oxide clusters with fumaric acid, a short organic acid linker, producing a compact, hydrophilic pore system with two distinct tetrahedral cage environments and one larger octahedral pore.

That pore geometry is what makes the material useful for pulling water out of dry air. At very low humidity the material adsorbs little water, but uptake rises sharply once relative humidity reaches roughly 10%, then plateaus — meaning the material is a poor humidity sponge until a threshold is crossed, then rapidly saturates. Water molecules first hydrogen-bond to the zirconium clusters inside the tetrahedral pores; only once those are full do additional water molecules begin clustering in the octahedral pores, bonding to each other rather than to the framework. That weaker water-water bonding in the later-filling pores is what lets the material release its water readily under mild heating, rather than requiring the high regeneration temperatures (around 120°C for silica gel) that make conventional desiccants energy-intensive.

Because 20% relative humidity at 25°C is equivalent to under 3% relative humidity at 65°C, a MOF-801 bed saturated at ambient desert conditions can be driven to release nearly all its stored water with a temperature rise of only about 40°C — achievable with simple, unconcentrated sunlight heating a dark absorber panel, with no external power input. This property was demonstrated in a 2017 device built by Hyunho Kim in Evelyn Wang’s MIT lab, in collaboration with Yaghi: air passes over MOF-801-infused copper foam in an open chamber until saturated, the chamber is sealed, and passive solar heating drives water vapor onto an ambient-temperature condenser. The prototype used less than 2 grams of MOF-801 and produced only fractions of a milliliter, but the researchers calculated that a thinner MOF layer capable of 12 heat/cool cycles per day could yield roughly 2.8 liters of water per kilogram of MOF-801 daily at 20% relative humidity, with no active refrigeration required if the condenser were passively heat-sunk instead.

MOF-801 also shows strong structural stability across repeated adsorption-desorption cycles and outperforms conventional desiccants at low humidity: reported adsorption capacity under low-humidity conditions runs roughly 190% that of silica gel and 132% that of 13X molecular sieve.

Notable Developments

  • 2026-01: Atoco, the company founded by Omar Yaghi to commercialize MOF-based AWH, targets field tests of containerized industrial AWH prototypes with commercial rollout planned for late 2026, with agriculture (controlled-environment agriculture / greenhouses) as an initial target market.
  • 2025-10: Omar Yaghi awarded the 2025 Nobel Prize in Chemistry (shared with Susumu Kitagawa and Richard Robson) for the development of metal-organic frameworks, directly citing MOF applications including water harvesting.
  • 2017-04: Yaghi (UC Berkeley) and Evelyn Wang (MIT), with student Hyunho Kim, published and demonstrated a passive solar-powered water harvester using MOF-801, operating at relative humidity as low as 20% with no external energy input beyond ambient sunlight (published in Science).
  • 2014: Yaghi’s group (Furukawa, Gándara, Zhang, Jiang, Queen, Hudson, Yaghi) first identified MOF-801’s advantageous water-adsorption properties in a systematic study of MOFs for water capture, published in the Journal of the American Chemical Society.

Key People / Key Organizations

  • Omar Yaghi — Professor of Chemistry, UC Berkeley; originated MOF-801 and the broader reticular chemistry field; 2025 Nobel Laureate in Chemistry. Also founder of Atoco, which commercializes this material. See the Atoco entry for full biographical detail.
  • Evelyn Wang — Mechanical engineering professor, MIT, who co-developed the solar-powered MOF-801 water harvesting device with Yaghi’s lab; brought thermal-systems engineering expertise to the water-release mechanism.
  • Hyunho Kim — MIT graduate student (Wang’s lab) who designed and built the 2017 proof-of-principle water harvester device.

People — Last Reviewed: 2026-07-15

Claim Verification

Claim: “MOF-801 can harvest water from air at relative humidity as low as 20%, releasing it with a 40°C temperature swing”

Status: Verified

Supporting sources:

  • Physics Today — describes the sharp water-uptake curve above ~10% RH and confirms the 25°C→65°C regeneration swing based on published isotherm data, citing the original Kim et al. 2017 Science paper (DOI: 10.1126/science.aam8743) and the 2014 JACS paper that first identified the property
  • ACS Central Science review (Xu & Yaghi, 2020) — co-authored by Omar Yaghi, surveys MOF water-harvesting materials including MOF-801’s low-humidity uptake behavior

Summary: Well-supported by science journalism coverage that closely tracks the peer-reviewed source publications, plus a co-authored review article; the original Science paper itself (paywalled) was not independently accessible during this review.

Claim: “A MOF-801 device can produce up to 2.8 liters of water per kilogram of MOF per day”

Status: Partially verified

Supporting sources:

  • Physics Today — reports this as a researcher estimate/calculation for an optimized device performing 12 daily heat/cool cycles, not a figure achieved by the actual 2017 prototype (which used under 2g of material and produced only fractions of a milliliter)

Refuting / questioning sources:

  • None found questioning the calculation itself, but the figure is explicitly a projected/estimated upper bound rather than a measured result from a fielded device at that scale.

Summary: The 2.8 L/kg/day figure is a credible researcher projection based on published uptake data, but it was not the measured output of the demonstrated prototype — treat it as a theoretical ceiling under specific cycling assumptions, not an achieved field result.

Sources

next →