A new study offers low-cost hydrogen production in a wire: Silicon nanowires could be used to split water into hydrogen and oxygen by converting light into electricity in a potential breakthrough for low-cost green hydrogen production, according to research published by Nature earlier this month. The new findings may be the gateway to more efficient, low-cost production of green hydrogen, potentially accelerating the roll out of the sustainable fuel.

SOUND SMART- Nanowires are wires with a thickness of only a few nanometres — a metric equivalent to one billionth of a meter. Previous studies have found that a semi-liquid mixture of nanoparticles — called particle suspension reactors (PSRs) — can absorb sunlight and use the energy to convert liquid water into oxygen and hydrogen gas.

Why add silicon to the mixture? Most demonstrations of PSRs were unsuccessful in generating enough energy for water splitting given that the semi-liquid mixture is only able to absorb ultraviolet light, leaving visible and infrared light unutilized, a summary of the paper explains. Silicon however, absorbs both visible and infrared light, which means it can absorb more sunlight to produce hydrogen more effectively.

The new design is inspired by solar panel technology: Even with the addition of silicon, the nanowires may not have enough photovoltaic particles — particles that convert light into electricity — to produce hydrogen from water. This prompted the researchers to encode multiple photovoltaic cells in each silicon particle, designing the silicon nanowires to have multiple “solar cells” along their axis to produce enough power needed to split water.

Lower hydrogen production cost is crucial for the energy transition: The global and regional hydrogen economy have both been riddled with technological and infrastructure barriers. A study published last December found that steam methane reforming and coal continue to dominate the supply side of hydrogen given their low production costs of under USD 3.50 per kg compared to USD 10 per kg for solar-powered hydrogen production. This leaves little room for economic incentive to transition to a cleaner fuel supply.

Why does it matter? According to the International Energy Agency, hydrogen demand in 2021 was almost entirely met by “unabated fossil fuel-based hydrogen” — producing CO2 emissions over 900 mega tons — while low-emission hydrogen production represented less than 1% of global hydrogen production.

And we already know MENA has ambitious hydrogen development plans: In November, MEED estimated over 50 signed projects in the region would net over USD 150 bn in investments. With the increasing interest in hydrogen production in the region, new tech advancement in hydrogen production could help in improving the feasibility of mega projects, especially as most are still in the preliminary stage. Major energy companies in the region have large-scale plans in place to produce green fuel including Masdar, Adnoc, Acwa Power, and Fertiglobe.

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