Small coupons cut from Mo foil are heated in static air at 600°C for approximately 2 hours. The metal coupons disintegrate into debris due to large volume change. The debris is heated for 1 hour at 450°C in a gas mixture containing 1% CO in N2, followed by natural cooling in air, forming very thin and sharp 2D platelets of MoO3. SEM and XRD are performed to confirm phase and morphology.

Mo powder is dissolved in H₂O₂ under vigorous stirring to form peroxomolybdic solution. HMTA solutions of varying molarity are prepared and slowly added to the peroxomolybdic solution under constant stirring, forming a precipitate. The precipitate is separated by centrifuge and dried at 70°C.

Ammonium molybdate is dissolved in DI water, followed by addition of urea (20 wt.%) and sonication in a water bath maintained at 65–70°C. pH is adjusted to ~3.0 by adding nitric acid while sonicating. The precipitate is collected by centrifuge and dried at 70°C.

Small coupons cut from W foil are heated in static air for 2 hours at 800°C. The metal coupons disintegrate into small debris. SEM and XRD are performed to confirm formation of WO3.

6M HCl is added dropwise to 100 mL of a 15 mM solution of Na₂WO4·2H₂O cooled to 5–10°C with constant stirring. The suspension is centrifuged, washed repeatedly to pH ~6, poured into 200–300 mL DI water, ultrasonicated for 2 hours, and aged for 24–48 hours at room temperature for crystallization.

2M HCl is added dropwise to 20 mL Na₂WO4·2H₂O solution under constant stirring until a pale yellow precipitate is formed. The precipitate is transferred to 60 mL of 2M HCl and stirred continuously for 24 hours, followed by aging for 96 hours at 80°C. The precipitate is filtered, washed with DI water, and calcined at 500°C for 2 hours in air (heating rate: 5°C/min).

0.17 M urea solution is made by dissolving 4.9 g urea in 480 mL DI water. It is heated to near boiling and refluxed for approximately 20 min at 110°C. 1.1 M zinc nitrate solution (3.27 g dissolved in 20 mL DI water) is added to the refluxing urea solution, and the mixture is boiled for an additional 15 min (or 20–25 min in some embodiments). The resulting mixture is rapidly cooled and the precipitate is collected by centrifuge and dried.

Small coupons cut from Mo foil are heated in static air at 600°C for approximately 2 hours. The metal coupons disintegrate into debris due to large volume change. The debris is heated for 1 hour at 450°C in a gas mixture containing 1% CO in N2, followed by natural cooling in air, forming very thin and sharp 2D platelets of MoO3. SEM and XRD are performed to confirm phase and morphology.

Mo powder is dissolved in H₂O₂ under vigorous stirring to form peroxomolybdic solution. HMTA solutions of varying molarity are prepared and slowly added to the peroxomolybdic solution under constant stirring, forming a precipitate. The precipitate is separated by centrifuge and dried at 70°C.

Ammonium molybdate is dissolved in DI water, followed by addition of urea (20 wt.%) and sonication in a water bath maintained at 65–70°C. pH is adjusted to ~3.0 by adding nitric acid while sonicating. The precipitate is collected by centrifuge and dried at 70°C.

Small coupons cut from W foil are heated in static air for 2 hours at 800°C. The metal coupons disintegrate into small debris. SEM and XRD are performed to confirm formation of WO3.

6M HCl is added dropwise to 100 mL of a 15 mM solution of Na₂WO4·2H₂O cooled to 5–10°C with constant stirring. The suspension is centrifuged, washed repeatedly to pH ~6, poured into 200–300 mL DI water, ultrasonicated for 2 hours, and aged for 24–48 hours at room temperature for crystallization.

2M HCl is added dropwise to 20 mL Na₂WO4·2H₂O solution under constant stirring until a pale yellow precipitate is formed. The precipitate is transferred to 60 mL of 2M HCl and stirred continuously for 24 hours, followed by aging for 96 hours at 80°C. The precipitate is filtered, washed with DI water, and calcined at 500°C for 2 hours in air (heating rate: 5°C/min).

0.17 M urea solution is made by dissolving 4.9 g urea in 480 mL DI water. It is heated to near boiling and refluxed for approximately 20 min at 110°C. 1.1 M zinc nitrate solution (3.27 g dissolved in 20 mL DI water) is added to the refluxing urea solution, and the mixture is boiled for an additional 15 min (or 20–25 min in some embodiments). The resulting mixture is rapidly cooled and the precipitate is collected by centrifuge and dried.

Small coupons cut from Mo foil are heated in static air at 600°C for approximately 2 hours. The metal coupons disintegrate into debris due to large volume change. The debris is heated for 1 hour at 450°C in a gas mixture containing 1% CO in N2, followed by natural cooling in air, forming very thin and sharp 2D platelets of MoO3. SEM and XRD are performed to confirm phase and morphology.

Mo powder is dissolved in H₂O₂ under vigorous stirring to form peroxomolybdic solution. HMTA solutions of varying molarity are prepared and slowly added to the peroxomolybdic solution under constant stirring, forming a precipitate. The precipitate is separated by centrifuge and dried at 70°C.

Ammonium molybdate is dissolved in DI water, followed by addition of urea (20 wt.%) and sonication in a water bath maintained at 65–70°C. pH is adjusted to ~3.0 by adding nitric acid while sonicating. The precipitate is collected by centrifuge and dried at 70°C.

Small coupons cut from W foil are heated in static air for 2 hours at 800°C. The metal coupons disintegrate into small debris. SEM and XRD are performed to confirm formation of WO3.

6M HCl is added dropwise to 100 mL of a 15 mM solution of Na₂WO4·2H₂O cooled to 5–10°C with constant stirring. The suspension is centrifuged, washed repeatedly to pH ~6, poured into 200–300 mL DI water, ultrasonicated for 2 hours, and aged for 24–48 hours at room temperature for crystallization.

2M HCl is added dropwise to 20 mL Na₂WO4·2H₂O solution under constant stirring until a pale yellow precipitate is formed. The precipitate is transferred to 60 mL of 2M HCl and stirred continuously for 24 hours, followed by aging for 96 hours at 80°C. The precipitate is filtered, washed with DI water, and calcined at 500°C for 2 hours in air (heating rate: 5°C/min).

0.17 M urea solution is made by dissolving 4.9 g urea in 480 mL DI water. It is heated to near boiling and refluxed for approximately 20 min at 110°C. 1.1 M zinc nitrate solution (3.27 g dissolved in 20 mL DI water) is added to the refluxing urea solution, and the mixture is boiled for an additional 15 min (or 20–25 min in some embodiments). The resulting mixture is rapidly cooled and the precipitate is collected by centrifuge and dried.

Small coupons cut from Mo foil are heated in static air at 600°C for approximately 2 hours. The metal coupons disintegrate into debris due to large volume change. The debris is heated for 1 hour at 450°C in a gas mixture containing 1% CO in N2, followed by natural cooling in air, forming very thin and sharp 2D platelets of MoO3. SEM and XRD are performed to confirm phase and morphology.

Mo powder is dissolved in H₂O₂ under vigorous stirring to form peroxomolybdic solution. HMTA solutions of varying molarity are prepared and slowly added to the peroxomolybdic solution under constant stirring, forming a precipitate. The precipitate is separated by centrifuge and dried at 70°C.

Ammonium molybdate is dissolved in DI water, followed by addition of urea (20 wt.%) and sonication in a water bath maintained at 65–70°C. pH is adjusted to ~3.0 by adding nitric acid while sonicating. The precipitate is collected by centrifuge and dried at 70°C.

Small coupons cut from W foil are heated in static air for 2 hours at 800°C. The metal coupons disintegrate into small debris. SEM and XRD are performed to confirm formation of WO3.

6M HCl is added dropwise to 100 mL of a 15 mM solution of Na₂WO4·2H₂O cooled to 5–10°C with constant stirring. The suspension is centrifuged, washed repeatedly to pH ~6, poured into 200–300 mL DI water, ultrasonicated for 2 hours, and aged for 24–48 hours at room temperature for crystallization.

2M HCl is added dropwise to 20 mL Na₂WO4·2H₂O solution under constant stirring until a pale yellow precipitate is formed. The precipitate is transferred to 60 mL of 2M HCl and stirred continuously for 24 hours, followed by aging for 96 hours at 80°C. The precipitate is filtered, washed with DI water, and calcined at 500°C for 2 hours in air (heating rate: 5°C/min).

0.17 M urea solution is made by dissolving 4.9 g urea in 480 mL DI water. It is heated to near boiling and refluxed for approximately 20 min at 110°C. 1.1 M zinc nitrate solution (3.27 g dissolved in 20 mL DI water) is added to the refluxing urea solution, and the mixture is boiled for an additional 15 min (or 20–25 min in some embodiments). The resulting mixture is rapidly cooled and the precipitate is collected by centrifuge and dried.